Merge branch 'dev' into 20260210-serial-proxy

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

.clang-tidy.hash

@@ -1 +1 @@
-9c4da80001128f05bb3bb3668a18609eea86e0b56bb04a22e66c7ec6609f92ff
+ce05c28e9dc0b12c4f6e7454986ffea5123ac974a949da841be698c535f2083e

.github/actions/build-image/action.yaml

@@ -47,7 +47,7 @@ runs:
 
     - name: Build and push to ghcr by digest
       id: build-ghcr
-      uses: docker/build-push-action@601a80b39c9405e50806ae38af30926f9d957c47 # v6.19.1
+      uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6.19.2
       env:
         DOCKER_BUILD_SUMMARY: false
         DOCKER_BUILD_RECORD_UPLOAD: false
@@ -73,7 +73,7 @@ runs:
 
     - name: Build and push to dockerhub by digest
       id: build-dockerhub
-      uses: docker/build-push-action@601a80b39c9405e50806ae38af30926f9d957c47 # v6.19.1
+      uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6.19.2
       env:
         DOCKER_BUILD_SUMMARY: false
         DOCKER_BUILD_RECORD_UPLOAD: false

CODEOWNERS

@@ -411,6 +411,7 @@ esphome/components/rp2040_pwm/* @jesserockz
 esphome/components/rpi_dpi_rgb/* @clydebarrow
 esphome/components/rtl87xx/* @kuba2k2
 esphome/components/rtttl/* @glmnet
+esphome/components/runtime_image/* @clydebarrow @guillempages @kahrendt
 esphome/components/runtime_stats/* @bdraco
 esphome/components/rx8130/* @beormund
 esphome/components/safe_mode/* @jsuanet @kbx81 @paulmonigatti
@@ -429,6 +430,7 @@ esphome/components/sen21231/* @shreyaskarnik
 esphome/components/sen5x/* @martgras
 esphome/components/sensirion_common/* @martgras
 esphome/components/sensor/* @esphome/core
+esphome/components/serial_proxy/* @kbx81
 esphome/components/sfa30/* @ghsensdev
 esphome/components/sgp40/* @SenexCrenshaw
 esphome/components/sgp4x/* @martgras @SenexCrenshaw

docker/Dockerfile

@@ -9,7 +9,8 @@ FROM ghcr.io/esphome/docker-base:${BUILD_OS}-ha-addon-${BUILD_BASE_VERSION} AS b
 ARG BUILD_TYPE
 FROM base-source-${BUILD_TYPE} AS base
 
-RUN git config --system --add safe.directory "*"
+RUN git config --system --add safe.directory "*" \
+    && git config --system advice.detachedHead false
 
 # Install build tools for Python packages that require compilation
 # (e.g., ruamel.yaml.clibz used by ESP-IDF's idf-component-manager)

esphome/analyze_memory/const.py

@@ -256,7 +256,7 @@ SYMBOL_PATTERNS = {
     "ipv6_stack": ["nd6_", "ip6_", "mld6_", "icmp6_", "icmp6_input"],
     # Order matters! More specific categories must come before general ones.
     # mdns must come before bluetooth to avoid "_mdns_disable_pcb" matching "ble_" pattern
-    "mdns_lib": ["mdns"],
+    "mdns_lib": ["mdns", "packet$"],
     # memory_mgmt must come before wifi_stack to catch mmu_hal_* symbols
     "memory_mgmt": [
         "mem_",
@@ -794,7 +794,6 @@ SYMBOL_PATTERNS = {
         "s_dp",
         "s_ni",
         "s_reg_dump",
-        "packet$",
         "d_mult_table",
         "K",
         "fcstab",

esphome/components/api/api.proto

@@ -69,6 +69,12 @@ service APIConnection {
   rpc zwave_proxy_request(ZWaveProxyRequest) returns (void) {}
 
   rpc infrared_rf_transmit_raw_timings(InfraredRFTransmitRawTimingsRequest) returns (void) {}
+
+  rpc serial_proxy_configure(SerialProxyConfigureRequest) returns (void) {}
+  rpc serial_proxy_write(SerialProxyWriteRequest) returns (void) {}
+  rpc serial_proxy_set_modem_pins(SerialProxySetModemPinsRequest) returns (void) {}
+  rpc serial_proxy_get_modem_pins(SerialProxyGetModemPinsRequest) returns (void) {}
+  rpc serial_proxy_request(SerialProxyRequest) returns (void) {}
 }
 
 
@@ -198,6 +204,17 @@ message DeviceInfo {
   uint32 area_id = 3;
 }
 
+enum SerialProxyPortType {
+  SERIAL_PROXY_PORT_TYPE_TTL = 0;
+  SERIAL_PROXY_PORT_TYPE_RS232 = 1;
+  SERIAL_PROXY_PORT_TYPE_RS485 = 2;
+}
+
+message SerialProxyInfo {
+  string name = 1;                    // Human-readable port name
+  SerialProxyPortType port_type = 2;  // Port type (RS232, RS485)
+}
+
 message DeviceInfoResponse {
   option (id) = 10;
   option (source) = SOURCE_SERVER;
@@ -260,6 +277,9 @@ message DeviceInfoResponse {
   // Indicates if Z-Wave proxy support is available and features supported
   uint32 zwave_proxy_feature_flags = 23 [(field_ifdef) = "USE_ZWAVE_PROXY"];
   uint32 zwave_home_id = 24 [(field_ifdef) = "USE_ZWAVE_PROXY"];
+
+  // Serial proxy instance metadata
+  repeated SerialProxyInfo serial_proxies = 25 [(field_ifdef) = "USE_SERIAL_PROXY", (fixed_array_size_define) = "SERIAL_PROXY_COUNT"];
 }
 
 message ListEntitiesRequest {
@@ -2488,3 +2508,92 @@ message InfraredRFReceiveEvent {
   fixed32 key = 2;                                    // Key identifying the receiver instance
   repeated sint32 timings = 3 [packed = true, (container_pointer_no_template) = "std::vector<int32_t>"];  // Raw timings in microseconds (zigzag-encoded): alternating mark/space periods
 }
+
+// ==================== SERIAL PROXY ====================
+
+enum SerialProxyParity {
+  SERIAL_PROXY_PARITY_NONE = 0;
+  SERIAL_PROXY_PARITY_EVEN = 1;
+  SERIAL_PROXY_PARITY_ODD = 2;
+}
+
+// Configure UART parameters for a serial proxy instance
+message SerialProxyConfigureRequest {
+  option (id) = 138;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;          // Instance index (0-based)
+  uint32 baudrate = 2;          // Baud rate in bits per second
+  bool flow_control = 3;        // Enable hardware flow control
+  SerialProxyParity parity = 4; // Parity setting
+  uint32 stop_bits = 5;         // Number of stop bits (1 or 2)
+  uint32 data_size = 6;         // Number of data bits (5-8)
+}
+
+// Data received from a serial device, forwarded to clients
+message SerialProxyDataReceived {
+  option (id) = 139;
+  option (source) = SOURCE_SERVER;
+  option (ifdef) = "USE_SERIAL_PROXY";
+  option (no_delay) = true;
+
+  uint32 instance = 1;          // Instance index (0-based)
+  bytes data = 2;               // Raw data received from the serial device
+}
+
+// Write data to a serial device
+message SerialProxyWriteRequest {
+  option (id) = 140;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+  option (no_delay) = true;
+
+  uint32 instance = 1;          // Instance index (0-based)
+  bytes data = 2;               // Raw data to write to the serial device
+}
+
+// Set modem control pin states (RTS and DTR)
+message SerialProxySetModemPinsRequest {
+  option (id) = 141;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;          // Instance index (0-based)
+  bool rts = 2;                 // Desired RTS pin state
+  bool dtr = 3;                 // Desired DTR pin state
+}
+
+// Request current modem control pin states
+message SerialProxyGetModemPinsRequest {
+  option (id) = 142;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;          // Instance index (0-based)
+}
+
+// Response with current modem control pin states
+message SerialProxyGetModemPinsResponse {
+  option (id) = 143;
+  option (source) = SOURCE_SERVER;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;          // Instance index (0-based)
+  bool rts = 2;                 // Current RTS pin state
+  bool dtr = 3;                 // Current DTR pin state
+}
+
+enum SerialProxyRequestType {
+  SERIAL_PROXY_REQUEST_TYPE_FLUSH = 0;  // Flush the serial port (block until all TX data is sent)
+}
+
+// Generic request message for simple serial proxy operations
+message SerialProxyRequest {
+  option (id) = 144;
+  option (source) = SOURCE_CLIENT;
+  option (ifdef) = "USE_SERIAL_PROXY";
+
+  uint32 instance = 1;                  // Instance index (0-based)
+  SerialProxyRequestType type = 2;      // Request type
+}

esphome/components/api/api_connection.cpp

@@ -1413,6 +1413,73 @@ void APIConnection::send_infrared_rf_receive_event(const InfraredRFReceiveEvent
 }
 #endif
 
+#ifdef USE_SERIAL_PROXY
+void APIConnection::on_serial_proxy_configure_request(const SerialProxyConfigureRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %u out of range (max %u)", msg.instance,
+             static_cast<uint32_t>(proxies.size()));
+    return;
+  }
+  proxies[msg.instance]->configure(msg.baudrate, msg.flow_control, static_cast<uint8_t>(msg.parity), msg.stop_bits,
+                                   msg.data_size);
+}
+
+void APIConnection::on_serial_proxy_write_request(const SerialProxyWriteRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    return;
+  }
+  proxies[msg.instance]->write(msg.data, msg.data_len);
+}
+
+void APIConnection::on_serial_proxy_set_modem_pins_request(const SerialProxySetModemPinsRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    return;
+  }
+  proxies[msg.instance]->set_modem_pins(msg.rts, msg.dtr);
+}
+
+void APIConnection::on_serial_proxy_get_modem_pins_request(const SerialProxyGetModemPinsRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    return;
+  }
+  bool rts, dtr;
+  proxies[msg.instance]->get_modem_pins(rts, dtr);
+
+  SerialProxyGetModemPinsResponse resp{};
+  resp.instance = msg.instance;
+  resp.rts = rts;
+  resp.dtr = dtr;
+  this->send_message(resp, SerialProxyGetModemPinsResponse::MESSAGE_TYPE);
+}
+
+void APIConnection::on_serial_proxy_request(const SerialProxyRequest &msg) {
+  auto &proxies = App.get_serial_proxies();
+  if (msg.instance >= proxies.size()) {
+    ESP_LOGW(TAG, "Serial proxy instance %u out of range", msg.instance);
+    return;
+  }
+  switch (msg.type) {
+    case enums::SERIAL_PROXY_REQUEST_TYPE_FLUSH:
+      proxies[msg.instance]->flush_port();
+      break;
+    default:
+      ESP_LOGW(TAG, "Unknown serial proxy request type: %u", static_cast<uint32_t>(msg.type));
+      break;
+  }
+}
+
+void APIConnection::send_serial_proxy_data(const SerialProxyDataReceived &msg) {
+  this->send_message(msg, SerialProxyDataReceived::MESSAGE_TYPE);
+}
+#endif
+
 #ifdef USE_INFRARED
 uint16_t APIConnection::try_send_infrared_info(EntityBase *entity, APIConnection *conn, uint32_t remaining_size) {
   auto *infrared = static_cast<infrared::Infrared *>(entity);
@@ -1627,6 +1694,16 @@ bool APIConnection::send_device_info_response_() {
   resp.zwave_proxy_feature_flags = zwave_proxy::global_zwave_proxy->get_feature_flags();
   resp.zwave_home_id = zwave_proxy::global_zwave_proxy->get_home_id();
 #endif
+#ifdef USE_SERIAL_PROXY
+  size_t serial_proxy_index = 0;
+  for (auto const &proxy : App.get_serial_proxies()) {
+    if (serial_proxy_index >= SERIAL_PROXY_COUNT)
+      break;
+    auto &info = resp.serial_proxies[serial_proxy_index++];
+    info.name = StringRef(proxy->get_name());
+    info.port_type = proxy->get_port_type();
+  }
+#endif
 #ifdef USE_API_NOISE
   resp.api_encryption_supported = true;
 #endif
@@ -1864,6 +1941,8 @@ void APIConnection::on_fatal_error() {
   this->flags_.remove = true;
 }
 
+void __attribute__((flatten)) APIConnection::DeferredBatch::push_item(const BatchItem &item) { items.push_back(item); }
+
 void APIConnection::DeferredBatch::add_item(EntityBase *entity, uint8_t message_type, uint8_t estimated_size,
                                             uint8_t aux_data_index) {
   // Check if we already have a message of this type for this entity
@@ -1880,7 +1959,7 @@ void APIConnection::DeferredBatch::add_item(EntityBase *entity, uint8_t message_
     }
   }
   // No existing item found (or event), add new one
-  items.push_back({entity, message_type, estimated_size, aux_data_index});
+  this->push_item({entity, message_type, estimated_size, aux_data_index});
 }
 
 void APIConnection::DeferredBatch::add_item_front(EntityBase *entity, uint8_t message_type, uint8_t estimated_size) {
@@ -1888,7 +1967,7 @@ void APIConnection::DeferredBatch::add_item_front(EntityBase *entity, uint8_t me
   // This avoids expensive vector::insert which shifts all elements
   // Note: We only ever have one high-priority message at a time (ping OR disconnect)
   // If we're disconnecting, pings are blocked, so this simple swap is sufficient
-  items.push_back({entity, message_type, estimated_size, AUX_DATA_UNUSED});
+  this->push_item({entity, message_type, estimated_size, AUX_DATA_UNUSED});
   if (items.size() > 1) {
     // Swap the new high-priority item to the front
     std::swap(items.front(), items.back());

esphome/components/api/api_connection.h

@@ -182,6 +182,15 @@ class APIConnection final : public APIServerConnectionBase {
   void send_infrared_rf_receive_event(const InfraredRFReceiveEvent &msg);
 #endif
 
+#ifdef USE_SERIAL_PROXY
+  void on_serial_proxy_configure_request(const SerialProxyConfigureRequest &msg) override;
+  void on_serial_proxy_write_request(const SerialProxyWriteRequest &msg) override;
+  void on_serial_proxy_set_modem_pins_request(const SerialProxySetModemPinsRequest &msg) override;
+  void on_serial_proxy_get_modem_pins_request(const SerialProxyGetModemPinsRequest &msg) override;
+  void on_serial_proxy_request(const SerialProxyRequest &msg) override;
+  void send_serial_proxy_data(const SerialProxyDataReceived &msg);
+#endif
+
 #ifdef USE_EVENT
   void send_event(event::Event *event);
 #endif
@@ -541,6 +550,8 @@ class APIConnection final : public APIServerConnectionBase {
                   uint8_t aux_data_index = AUX_DATA_UNUSED);
     // Add item to the front of the batch (for high priority messages like ping)
     void add_item_front(EntityBase *entity, uint8_t message_type, uint8_t estimated_size);
+    // Single push_back site to avoid duplicate _M_realloc_insert instantiation
+    void push_item(const BatchItem &item);
 
     // Clear all items
     void clear() {

esphome/components/api/api_frame_helper_noise.cpp

@@ -138,10 +138,12 @@ APIError APINoiseFrameHelper::handle_noise_error_(int err, const LogString *func
 
 /// Run through handshake messages (if in that phase)
 APIError APINoiseFrameHelper::loop() {
-  // During handshake phase, process as many actions as possible until we can't progress
-  // socket_->ready() stays true until next main loop, but state_action() will return
-  // WOULD_BLOCK when no more data is available to read
-  while (state_ != State::DATA && this->socket_->ready()) {
+  // Cache ready() outside the loop. On ESP8266 LWIP raw TCP, ready() returns false once
+  // the rx buffer is consumed. Re-checking each iteration would block handshake writes
+  // that must follow reads, deadlocking the handshake. state_action() will return
+  // WOULD_BLOCK when no more data is available to read.
+  bool socket_ready = this->socket_->ready();
+  while (state_ != State::DATA && socket_ready) {
     APIError err = state_action_();
     if (err == APIError::WOULD_BLOCK) {
       break;

esphome/components/api/api_pb2.cpp

@@ -65,6 +65,16 @@ void DeviceInfo::calculate_size(ProtoSize &size) const {
   size.add_uint32(1, this->area_id);
 }
 #endif
+#ifdef USE_SERIAL_PROXY
+void SerialProxyInfo::encode(ProtoWriteBuffer buffer) const {
+  buffer.encode_string(1, this->name);
+  buffer.encode_uint32(2, static_cast<uint32_t>(this->port_type));
+}
+void SerialProxyInfo::calculate_size(ProtoSize &size) const {
+  size.add_length(1, this->name.size());
+  size.add_uint32(1, static_cast<uint32_t>(this->port_type));
+}
+#endif
 void DeviceInfoResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_string(2, this->name);
   buffer.encode_string(3, this->mac_address);
@@ -119,6 +129,11 @@ void DeviceInfoResponse::encode(ProtoWriteBuffer buffer) const {
 #ifdef USE_ZWAVE_PROXY
   buffer.encode_uint32(24, this->zwave_home_id);
 #endif
+#ifdef USE_SERIAL_PROXY
+  for (const auto &it : this->serial_proxies) {
+    buffer.encode_message(25, it);
+  }
+#endif
 }
 void DeviceInfoResponse::calculate_size(ProtoSize &size) const {
   size.add_length(1, this->name.size());
@@ -174,6 +189,11 @@ void DeviceInfoResponse::calculate_size(ProtoSize &size) const {
 #ifdef USE_ZWAVE_PROXY
   size.add_uint32(2, this->zwave_home_id);
 #endif
+#ifdef USE_SERIAL_PROXY
+  for (const auto &it : this->serial_proxies) {
+    size.add_message_object_force(2, it);
+  }
+#endif
 }
 #ifdef USE_BINARY_SENSOR
 void ListEntitiesBinarySensorResponse::encode(ProtoWriteBuffer buffer) const {
@@ -3440,5 +3460,111 @@ void InfraredRFReceiveEvent::calculate_size(ProtoSize &size) const {
   }
 }
 #endif
+#ifdef USE_SERIAL_PROXY
+bool SerialProxyConfigureRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value.as_uint32();
+      break;
+    case 2:
+      this->baudrate = value.as_uint32();
+      break;
+    case 3:
+      this->flow_control = value.as_bool();
+      break;
+    case 4:
+      this->parity = static_cast<enums::SerialProxyParity>(value.as_uint32());
+      break;
+    case 5:
+      this->stop_bits = value.as_uint32();
+      break;
+    case 6:
+      this->data_size = value.as_uint32();
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+void SerialProxyDataReceived::encode(ProtoWriteBuffer buffer) const {
+  buffer.encode_uint32(1, this->instance);
+  buffer.encode_bytes(2, this->data_ptr_, this->data_len_);
+}
+void SerialProxyDataReceived::calculate_size(ProtoSize &size) const {
+  size.add_uint32(1, this->instance);
+  size.add_length(1, this->data_len_);
+}
+bool SerialProxyWriteRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value.as_uint32();
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+bool SerialProxyWriteRequest::decode_length(uint32_t field_id, ProtoLengthDelimited value) {
+  switch (field_id) {
+    case 2: {
+      this->data = value.data();
+      this->data_len = value.size();
+      break;
+    }
+    default:
+      return false;
+  }
+  return true;
+}
+bool SerialProxySetModemPinsRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value.as_uint32();
+      break;
+    case 2:
+      this->rts = value.as_bool();
+      break;
+    case 3:
+      this->dtr = value.as_bool();
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+bool SerialProxyGetModemPinsRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value.as_uint32();
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+void SerialProxyGetModemPinsResponse::encode(ProtoWriteBuffer buffer) const {
+  buffer.encode_uint32(1, this->instance);
+  buffer.encode_bool(2, this->rts);
+  buffer.encode_bool(3, this->dtr);
+}
+void SerialProxyGetModemPinsResponse::calculate_size(ProtoSize &size) const {
+  size.add_uint32(1, this->instance);
+  size.add_bool(1, this->rts);
+  size.add_bool(1, this->dtr);
+}
+bool SerialProxyRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
+  switch (field_id) {
+    case 1:
+      this->instance = value.as_uint32();
+      break;
+    case 2:
+      this->type = static_cast<enums::SerialProxyRequestType>(value.as_uint32());
+      break;
+    default:
+      return false;
+  }
+  return true;
+}
+#endif
 
 }  // namespace esphome::api

esphome/components/api/api_pb2.h

@@ -12,6 +12,11 @@ namespace esphome::api {
 
 namespace enums {
 
+enum SerialProxyPortType : uint32_t {
+  SERIAL_PROXY_PORT_TYPE_TTL = 0,
+  SERIAL_PROXY_PORT_TYPE_RS232 = 1,
+  SERIAL_PROXY_PORT_TYPE_RS485 = 2,
+};
 enum EntityCategory : uint32_t {
   ENTITY_CATEGORY_NONE = 0,
   ENTITY_CATEGORY_CONFIG = 1,
@@ -311,6 +316,16 @@ enum ZWaveProxyRequestType : uint32_t {
   ZWAVE_PROXY_REQUEST_TYPE_HOME_ID_CHANGE = 2,
 };
 #endif
+#ifdef USE_SERIAL_PROXY
+enum SerialProxyParity : uint32_t {
+  SERIAL_PROXY_PARITY_NONE = 0,
+  SERIAL_PROXY_PARITY_EVEN = 1,
+  SERIAL_PROXY_PARITY_ODD = 2,
+};
+enum SerialProxyRequestType : uint32_t {
+  SERIAL_PROXY_REQUEST_TYPE_FLUSH = 0,
+};
+#endif
 
 }  // namespace enums
 
@@ -471,10 +486,24 @@ class DeviceInfo final : public ProtoMessage {
  protected:
 };
 #endif
+#ifdef USE_SERIAL_PROXY
+class SerialProxyInfo final : public ProtoMessage {
+ public:
+  StringRef name{};
+  enums::SerialProxyPortType port_type{};
+  void encode(ProtoWriteBuffer buffer) const override;
+  void calculate_size(ProtoSize &size) const override;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+};
+#endif
 class DeviceInfoResponse final : public ProtoMessage {
  public:
   static constexpr uint8_t MESSAGE_TYPE = 10;
-  static constexpr uint8_t ESTIMATED_SIZE = 255;
+  static constexpr uint16_t ESTIMATED_SIZE = 309;
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "device_info_response"; }
 #endif
@@ -526,6 +555,9 @@ class DeviceInfoResponse final : public ProtoMessage {
 #endif
 #ifdef USE_ZWAVE_PROXY
   uint32_t zwave_home_id{0};
+#endif
+#ifdef USE_SERIAL_PROXY
+  std::array<SerialProxyInfo, SERIAL_PROXY_COUNT> serial_proxies{};
 #endif
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
@@ -3025,5 +3057,133 @@ class InfraredRFReceiveEvent final : public ProtoMessage {
  protected:
 };
 #endif
+#ifdef USE_SERIAL_PROXY
+class SerialProxyConfigureRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 138;
+  static constexpr uint8_t ESTIMATED_SIZE = 20;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_configure_request"; }
+#endif
+  uint32_t instance{0};
+  uint32_t baudrate{0};
+  bool flow_control{false};
+  enums::SerialProxyParity parity{};
+  uint32_t stop_bits{0};
+  uint32_t data_size{0};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_varint(uint32_t field_id, ProtoVarInt value) override;
+};
+class SerialProxyDataReceived final : public ProtoMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 139;
+  static constexpr uint8_t ESTIMATED_SIZE = 23;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_data_received"; }
+#endif
+  uint32_t instance{0};
+  const uint8_t *data_ptr_{nullptr};
+  size_t data_len_{0};
+  void set_data(const uint8_t *data, size_t len) {
+    this->data_ptr_ = data;
+    this->data_len_ = len;
+  }
+  void encode(ProtoWriteBuffer buffer) const override;
+  void calculate_size(ProtoSize &size) const override;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+};
+class SerialProxyWriteRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 140;
+  static constexpr uint8_t ESTIMATED_SIZE = 23;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_write_request"; }
+#endif
+  uint32_t instance{0};
+  const uint8_t *data{nullptr};
+  uint16_t data_len{0};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_length(uint32_t field_id, ProtoLengthDelimited value) override;
+  bool decode_varint(uint32_t field_id, ProtoVarInt value) override;
+};
+class SerialProxySetModemPinsRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 141;
+  static constexpr uint8_t ESTIMATED_SIZE = 8;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_set_modem_pins_request"; }
+#endif
+  uint32_t instance{0};
+  bool rts{false};
+  bool dtr{false};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_varint(uint32_t field_id, ProtoVarInt value) override;
+};
+class SerialProxyGetModemPinsRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 142;
+  static constexpr uint8_t ESTIMATED_SIZE = 4;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_get_modem_pins_request"; }
+#endif
+  uint32_t instance{0};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_varint(uint32_t field_id, ProtoVarInt value) override;
+};
+class SerialProxyGetModemPinsResponse final : public ProtoMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 143;
+  static constexpr uint8_t ESTIMATED_SIZE = 8;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_get_modem_pins_response"; }
+#endif
+  uint32_t instance{0};
+  bool rts{false};
+  bool dtr{false};
+  void encode(ProtoWriteBuffer buffer) const override;
+  void calculate_size(ProtoSize &size) const override;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+};
+class SerialProxyRequest final : public ProtoDecodableMessage {
+ public:
+  static constexpr uint8_t MESSAGE_TYPE = 144;
+  static constexpr uint8_t ESTIMATED_SIZE = 6;
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *message_name() const override { return "serial_proxy_request"; }
+#endif
+  uint32_t instance{0};
+  enums::SerialProxyRequestType type{};
+#ifdef HAS_PROTO_MESSAGE_DUMP
+  const char *dump_to(DumpBuffer &out) const override;
+#endif
+
+ protected:
+  bool decode_varint(uint32_t field_id, ProtoVarInt value) override;
+};
+#endif
 
 }  // namespace esphome::api

esphome/components/api/api_pb2_dump.cpp

@@ -100,6 +100,18 @@ static void dump_bytes_field(DumpBuffer &out, const char *field_name, const uint
   out.append(hex_buf).append("\n");
 }
 
+template<> const char *proto_enum_to_string<enums::SerialProxyPortType>(enums::SerialProxyPortType value) {
+  switch (value) {
+    case enums::SERIAL_PROXY_PORT_TYPE_TTL:
+      return "SERIAL_PROXY_PORT_TYPE_TTL";
+    case enums::SERIAL_PROXY_PORT_TYPE_RS232:
+      return "SERIAL_PROXY_PORT_TYPE_RS232";
+    case enums::SERIAL_PROXY_PORT_TYPE_RS485:
+      return "SERIAL_PROXY_PORT_TYPE_RS485";
+    default:
+      return "UNKNOWN";
+  }
+}
 template<> const char *proto_enum_to_string<enums::EntityCategory>(enums::EntityCategory value) {
   switch (value) {
     case enums::ENTITY_CATEGORY_NONE:
@@ -736,6 +748,28 @@ template<> const char *proto_enum_to_string<enums::ZWaveProxyRequestType>(enums:
   }
 }
 #endif
+#ifdef USE_SERIAL_PROXY
+template<> const char *proto_enum_to_string<enums::SerialProxyParity>(enums::SerialProxyParity value) {
+  switch (value) {
+    case enums::SERIAL_PROXY_PARITY_NONE:
+      return "SERIAL_PROXY_PARITY_NONE";
+    case enums::SERIAL_PROXY_PARITY_EVEN:
+      return "SERIAL_PROXY_PARITY_EVEN";
+    case enums::SERIAL_PROXY_PARITY_ODD:
+      return "SERIAL_PROXY_PARITY_ODD";
+    default:
+      return "UNKNOWN";
+  }
+}
+template<> const char *proto_enum_to_string<enums::SerialProxyRequestType>(enums::SerialProxyRequestType value) {
+  switch (value) {
+    case enums::SERIAL_PROXY_REQUEST_TYPE_FLUSH:
+      return "SERIAL_PROXY_REQUEST_TYPE_FLUSH";
+    default:
+      return "UNKNOWN";
+  }
+}
+#endif
 
 const char *HelloRequest::dump_to(DumpBuffer &out) const {
   MessageDumpHelper helper(out, "HelloRequest");
@@ -785,6 +819,14 @@ const char *DeviceInfo::dump_to(DumpBuffer &out) const {
   return out.c_str();
 }
 #endif
+#ifdef USE_SERIAL_PROXY
+const char *SerialProxyInfo::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyInfo");
+  dump_field(out, "name", this->name);
+  dump_field(out, "port_type", static_cast<enums::SerialProxyPortType>(this->port_type));
+  return out.c_str();
+}
+#endif
 const char *DeviceInfoResponse::dump_to(DumpBuffer &out) const {
   MessageDumpHelper helper(out, "DeviceInfoResponse");
   dump_field(out, "name", this->name);
@@ -845,6 +887,13 @@ const char *DeviceInfoResponse::dump_to(DumpBuffer &out) const {
 #endif
 #ifdef USE_ZWAVE_PROXY
   dump_field(out, "zwave_home_id", this->zwave_home_id);
+#endif
+#ifdef USE_SERIAL_PROXY
+  for (const auto &it : this->serial_proxies) {
+    out.append("  serial_proxies: ");
+    it.dump_to(out);
+    out.append("\n");
+  }
 #endif
   return out.c_str();
 }
@@ -2469,6 +2518,55 @@ const char *InfraredRFReceiveEvent::dump_to(DumpBuffer &out) const {
   return out.c_str();
 }
 #endif
+#ifdef USE_SERIAL_PROXY
+const char *SerialProxyConfigureRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyConfigureRequest");
+  dump_field(out, "instance", this->instance);
+  dump_field(out, "baudrate", this->baudrate);
+  dump_field(out, "flow_control", this->flow_control);
+  dump_field(out, "parity", static_cast<enums::SerialProxyParity>(this->parity));
+  dump_field(out, "stop_bits", this->stop_bits);
+  dump_field(out, "data_size", this->data_size);
+  return out.c_str();
+}
+const char *SerialProxyDataReceived::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyDataReceived");
+  dump_field(out, "instance", this->instance);
+  dump_bytes_field(out, "data", this->data_ptr_, this->data_len_);
+  return out.c_str();
+}
+const char *SerialProxyWriteRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyWriteRequest");
+  dump_field(out, "instance", this->instance);
+  dump_bytes_field(out, "data", this->data, this->data_len);
+  return out.c_str();
+}
+const char *SerialProxySetModemPinsRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxySetModemPinsRequest");
+  dump_field(out, "instance", this->instance);
+  dump_field(out, "rts", this->rts);
+  dump_field(out, "dtr", this->dtr);
+  return out.c_str();
+}
+const char *SerialProxyGetModemPinsRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyGetModemPinsRequest");
+  dump_field(out, "instance", this->instance);
+  return out.c_str();
+}
+const char *SerialProxyGetModemPinsResponse::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyGetModemPinsResponse");
+  dump_field(out, "instance", this->instance);
+  dump_field(out, "rts", this->rts);
+  dump_field(out, "dtr", this->dtr);
+  return out.c_str();
+}
+const char *SerialProxyRequest::dump_to(DumpBuffer &out) const {
+  MessageDumpHelper helper(out, "SerialProxyRequest");
+  dump_field(out, "instance", this->instance);
+  dump_field(out, "type", static_cast<enums::SerialProxyRequestType>(this->type));
+  return out.c_str();
+}
+#endif
 
 }  // namespace esphome::api
 

esphome/components/api/api_pb2_service.cpp

@@ -634,6 +634,61 @@ void APIServerConnectionBase::read_message(uint32_t msg_size, uint32_t msg_type,
       this->on_infrared_rf_transmit_raw_timings_request(msg);
       break;
     }
+#endif
+#ifdef USE_SERIAL_PROXY
+    case SerialProxyConfigureRequest::MESSAGE_TYPE: {
+      SerialProxyConfigureRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_configure_request"), msg);
+#endif
+      this->on_serial_proxy_configure_request(msg);
+      break;
+    }
+#endif
+#ifdef USE_SERIAL_PROXY
+    case SerialProxyWriteRequest::MESSAGE_TYPE: {
+      SerialProxyWriteRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_write_request"), msg);
+#endif
+      this->on_serial_proxy_write_request(msg);
+      break;
+    }
+#endif
+#ifdef USE_SERIAL_PROXY
+    case SerialProxySetModemPinsRequest::MESSAGE_TYPE: {
+      SerialProxySetModemPinsRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_set_modem_pins_request"), msg);
+#endif
+      this->on_serial_proxy_set_modem_pins_request(msg);
+      break;
+    }
+#endif
+#ifdef USE_SERIAL_PROXY
+    case SerialProxyGetModemPinsRequest::MESSAGE_TYPE: {
+      SerialProxyGetModemPinsRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_get_modem_pins_request"), msg);
+#endif
+      this->on_serial_proxy_get_modem_pins_request(msg);
+      break;
+    }
+#endif
+#ifdef USE_SERIAL_PROXY
+    case SerialProxyRequest::MESSAGE_TYPE: {
+      SerialProxyRequest msg;
+      msg.decode(msg_data, msg_size);
+#ifdef HAS_PROTO_MESSAGE_DUMP
+      this->log_receive_message_(LOG_STR("on_serial_proxy_request"), msg);
+#endif
+      this->on_serial_proxy_request(msg);
+      break;
+    }
 #endif
     default:
       break;

esphome/components/api/api_pb2_service.h

@@ -224,6 +224,23 @@ class APIServerConnectionBase : public ProtoService {
   virtual void on_infrared_rf_transmit_raw_timings_request(const InfraredRFTransmitRawTimingsRequest &value){};
 #endif
 
+#ifdef USE_SERIAL_PROXY
+  virtual void on_serial_proxy_configure_request(const SerialProxyConfigureRequest &value){};
+#endif
+
+#ifdef USE_SERIAL_PROXY
+  virtual void on_serial_proxy_write_request(const SerialProxyWriteRequest &value){};
+#endif
+#ifdef USE_SERIAL_PROXY
+  virtual void on_serial_proxy_set_modem_pins_request(const SerialProxySetModemPinsRequest &value){};
+#endif
+#ifdef USE_SERIAL_PROXY
+  virtual void on_serial_proxy_get_modem_pins_request(const SerialProxyGetModemPinsRequest &value){};
+#endif
+
+#ifdef USE_SERIAL_PROXY
+  virtual void on_serial_proxy_request(const SerialProxyRequest &value){};
+#endif
  protected:
   void read_message(uint32_t msg_size, uint32_t msg_type, const uint8_t *msg_data) override;
 };

esphome/components/api/api_server.cpp

@@ -117,37 +117,7 @@ void APIServer::setup() {
 void APIServer::loop() {
   // Accept new clients only if the socket exists and has incoming connections
   if (this->socket_ && this->socket_->ready()) {
-    while (true) {
-      struct sockaddr_storage source_addr;
-      socklen_t addr_len = sizeof(source_addr);
-
-      auto sock = this->socket_->accept_loop_monitored((struct sockaddr *) &source_addr, &addr_len);
-      if (!sock)
-        break;
-
-      char peername[socket::SOCKADDR_STR_LEN];
-      sock->getpeername_to(peername);
-
-      // Check if we're at the connection limit
-      if (this->clients_.size() >= this->max_connections_) {
-        ESP_LOGW(TAG, "Max connections (%d), rejecting %s", this->max_connections_, peername);
-        // Immediately close - socket destructor will handle cleanup
-        sock.reset();
-        continue;
-      }
-
-      ESP_LOGD(TAG, "Accept %s", peername);
-
-      auto *conn = new APIConnection(std::move(sock), this);
-      this->clients_.emplace_back(conn);
-      conn->start();
-
-      // First client connected - clear warning and update timestamp
-      if (this->clients_.size() == 1 && this->reboot_timeout_ != 0) {
-        this->status_clear_warning();
-        this->last_connected_ = App.get_loop_component_start_time();
-      }
-    }
+    this->accept_new_connections_();
   }
 
   if (this->clients_.empty()) {
@@ -178,46 +148,88 @@ void APIServer::loop() {
   while (client_index < this->clients_.size()) {
     auto &client = this->clients_[client_index];
 
+    // Common case: process active client
     if (!client->flags_.remove) {
-      // Common case: process active client
       client->loop();
+    }
+    // Handle disconnection promptly - close socket to free LWIP PCB
+    // resources and prevent retransmit crashes on ESP8266.
+    if (client->flags_.remove) {
+      // Rare case: handle disconnection (don't increment - swapped element needs processing)
+      this->remove_client_(client_index);
+    } else {
       client_index++;
+    }
+  }
+}
+
+void APIServer::remove_client_(size_t client_index) {
+  auto &client = this->clients_[client_index];
+
+#ifdef USE_API_USER_DEFINED_ACTION_RESPONSES
+  this->unregister_active_action_calls_for_connection(client.get());
+#endif
+  ESP_LOGV(TAG, "Remove connection %s", client->get_name());
+
+#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
+  // Save client info before closing socket and removal for the trigger
+  char peername_buf[socket::SOCKADDR_STR_LEN];
+  std::string client_name(client->get_name());
+  std::string client_peername(client->get_peername_to(peername_buf));
+#endif
+
+  // Close socket now (was deferred from on_fatal_error to allow getpeername)
+  client->helper_->close();
+
+  // Swap with the last element and pop (avoids expensive vector shifts)
+  if (client_index < this->clients_.size() - 1) {
+    std::swap(this->clients_[client_index], this->clients_.back());
+  }
+  this->clients_.pop_back();
+
+  // Last client disconnected - set warning and start tracking for reboot timeout
+  if (this->clients_.empty() && this->reboot_timeout_ != 0) {
+    this->status_set_warning();
+    this->last_connected_ = App.get_loop_component_start_time();
+  }
+
+#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
+  // Fire trigger after client is removed so api.connected reflects the true state
+  this->client_disconnected_trigger_.trigger(client_name, client_peername);
+#endif
+}
+
+void __attribute__((flatten)) APIServer::accept_new_connections_() {
+  while (true) {
+    struct sockaddr_storage source_addr;
+    socklen_t addr_len = sizeof(source_addr);
+
+    auto sock = this->socket_->accept_loop_monitored((struct sockaddr *) &source_addr, &addr_len);
+    if (!sock)
+      break;
+
+    char peername[socket::SOCKADDR_STR_LEN];
+    sock->getpeername_to(peername);
+
+    // Check if we're at the connection limit
+    if (this->clients_.size() >= this->max_connections_) {
+      ESP_LOGW(TAG, "Max connections (%d), rejecting %s", this->max_connections_, peername);
+      // Immediately close - socket destructor will handle cleanup
+      sock.reset();
       continue;
     }
 
-    // Rare case: handle disconnection
-#ifdef USE_API_USER_DEFINED_ACTION_RESPONSES
-    this->unregister_active_action_calls_for_connection(client.get());
-#endif
-    ESP_LOGV(TAG, "Remove connection %s", client->get_name());
+    ESP_LOGD(TAG, "Accept %s", peername);
 
-#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
-    // Save client info before closing socket and removal for the trigger
-    char peername_buf[socket::SOCKADDR_STR_LEN];
-    std::string client_name(client->get_name());
-    std::string client_peername(client->get_peername_to(peername_buf));
-#endif
+    auto *conn = new APIConnection(std::move(sock), this);
+    this->clients_.emplace_back(conn);
+    conn->start();
 
-    // Close socket now (was deferred from on_fatal_error to allow getpeername)
-    client->helper_->close();
-
-    // Swap with the last element and pop (avoids expensive vector shifts)
-    if (client_index < this->clients_.size() - 1) {
-      std::swap(this->clients_[client_index], this->clients_.back());
-    }
-    this->clients_.pop_back();
-
-    // Last client disconnected - set warning and start tracking for reboot timeout
-    if (this->clients_.empty() && this->reboot_timeout_ != 0) {
-      this->status_set_warning();
+    // First client connected - clear warning and update timestamp
+    if (this->clients_.size() == 1 && this->reboot_timeout_ != 0) {
+      this->status_clear_warning();
       this->last_connected_ = App.get_loop_component_start_time();
     }
-
-#ifdef USE_API_CLIENT_DISCONNECTED_TRIGGER
-    // Fire trigger after client is removed so api.connected reflects the true state
-    this->client_disconnected_trigger_.trigger(client_name, client_peername);
-#endif
-    // Don't increment client_index since we need to process the swapped element
   }
 }
 
@@ -370,6 +382,17 @@ void APIServer::send_infrared_rf_receive_event([[maybe_unused]] uint32_t device_
 }
 #endif
 
+#ifdef USE_SERIAL_PROXY
+void APIServer::send_serial_proxy_data(uint32_t instance, const uint8_t *data, size_t len) {
+  SerialProxyDataReceived msg{};
+  msg.instance = instance;
+  msg.set_data(data, len);
+
+  for (auto &c : this->clients_)
+    c->send_serial_proxy_data(msg);
+}
+#endif
+
 #ifdef USE_ALARM_CONTROL_PANEL
 API_DISPATCH_UPDATE(alarm_control_panel::AlarmControlPanel, alarm_control_panel)
 #endif

esphome/components/api/api_server.h

@@ -189,6 +189,10 @@ class APIServer : public Component,
   void send_infrared_rf_receive_event(uint32_t device_id, uint32_t key, const std::vector<int32_t> *timings);
 #endif
 
+#ifdef USE_SERIAL_PROXY
+  void send_serial_proxy_data(uint32_t instance, const uint8_t *data, size_t len);
+#endif
+
   bool is_connected(bool state_subscription_only = false) const;
 
 #ifdef USE_API_HOMEASSISTANT_STATES
@@ -234,6 +238,11 @@ class APIServer : public Component,
 #endif
 
  protected:
+  // Accept incoming socket connections. Only called when socket has pending connections.
+  void __attribute__((noinline)) accept_new_connections_();
+  // Remove a disconnected client by index. Swaps with last element and pops.
+  void __attribute__((noinline)) remove_client_(size_t client_index);
+
 #ifdef USE_API_NOISE
   bool update_noise_psk_(const SavedNoisePsk &new_psk, const LogString *save_log_msg, const LogString *fail_log_msg,
                          const psk_t &active_psk, bool make_active);

esphome/components/captive_portal/captive_portal.cpp

@@ -47,8 +47,8 @@ void CaptivePortal::handle_config(AsyncWebServerRequest *request) {
   request->send(stream);
 }
 void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
-  std::string ssid = request->arg("ssid").c_str();  // NOLINT(readability-redundant-string-cstr)
-  std::string psk = request->arg("psk").c_str();    // NOLINT(readability-redundant-string-cstr)
+  const auto &ssid = request->arg("ssid");
+  const auto &psk = request->arg("psk");
   ESP_LOGI(TAG,
            "Requested WiFi Settings Change:\n"
            "  SSID='%s'\n"
@@ -56,10 +56,10 @@ void CaptivePortal::handle_wifisave(AsyncWebServerRequest *request) {
            ssid.c_str(), psk.c_str());
 #ifdef USE_ESP8266
   // ESP8266 is single-threaded, call directly
-  wifi::global_wifi_component->save_wifi_sta(ssid, psk);
+  wifi::global_wifi_component->save_wifi_sta(ssid.c_str(), psk.c_str());
 #else
   // Defer save to main loop thread to avoid NVS operations from HTTP thread
-  this->defer([ssid, psk]() { wifi::global_wifi_component->save_wifi_sta(ssid, psk); });
+  this->defer([ssid, psk]() { wifi::global_wifi_component->save_wifi_sta(ssid.c_str(), psk.c_str()); });
 #endif
   request->redirect(ESPHOME_F("/?save"));
 }

esphome/components/esp32/__init__.py

@@ -613,13 +613,9 @@ def _format_framework_arduino_version(ver: cv.Version) -> str:
     return f"{ARDUINO_FRAMEWORK_PKG}@https://github.com/espressif/arduino-esp32/releases/download/{ver}/{filename}"
 
 
-def _format_framework_espidf_version(
-    ver: cv.Version, release: str | None = None
-) -> str:
+def _format_framework_espidf_version(ver: cv.Version, release: str) -> str:
     # format the given espidf (https://github.com/pioarduino/esp-idf/releases) version to
     # a PIO platformio/framework-espidf value
-    if release is None:
-        release = ESP_IDF_RELEASE_LOOKUP.get(ver)
     if ver == cv.Version(5, 4, 3) or ver >= cv.Version(5, 5, 1):
         ext = "tar.xz"
     else:
@@ -696,9 +692,6 @@ ESP_IDF_FRAMEWORK_VERSION_LOOKUP = {
     "latest": cv.Version(5, 5, 2),
     "dev": cv.Version(5, 5, 2),
 }
-ESP_IDF_RELEASE_LOOKUP: dict[cv.Version, str] = {
-    cv.Version(5, 5, 2): "260206",
-}
 ESP_IDF_PLATFORM_VERSION_LOOKUP = {
     cv.Version(5, 5, 2): cv.Version(55, 3, 37),
     cv.Version(5, 5, 1): cv.Version(55, 3, 31, "2"),
@@ -762,7 +755,7 @@ def _check_versions(config):
         platform_lookup = ESP_IDF_PLATFORM_VERSION_LOOKUP.get(version)
         value[CONF_SOURCE] = value.get(
             CONF_SOURCE,
-            _format_framework_espidf_version(version, value.get(CONF_RELEASE)),
+            _format_framework_espidf_version(version, value.get(CONF_RELEASE, None)),
         )
         if _is_framework_url(value[CONF_SOURCE]):
             value[CONF_SOURCE] = f"pioarduino/framework-espidf@{value[CONF_SOURCE]}"
@@ -1474,7 +1467,7 @@ async def to_code(config):
             if (idf_ver := ARDUINO_IDF_VERSION_LOOKUP.get(framework_ver)) is not None:
                 cg.add_platformio_option(
                     "platform_packages",
-                    [_format_framework_espidf_version(idf_ver)],
+                    [_format_framework_espidf_version(idf_ver, None)],
                 )
                 # Use stub package to skip downloading precompiled libs
                 stubs_dir = CORE.relative_build_path("arduino_libs_stub")
@@ -1518,14 +1511,6 @@ async def to_code(config):
         f"CONFIG_ESPTOOLPY_FLASHSIZE_{config[CONF_FLASH_SIZE]}", True
     )
 
-    # ESP32-P4: The ESP-IDF 5.5.2.260206 release changed the default of
-    # ESP32P4_SELECTS_REV_LESS_V3 from y to n. PlatformIO always uses
-    # sections.ld.in (for rev <3) rather than sections.rev3.ld.in (for rev >=3),
-    # causing a linker script mismatch with the generated memory.ld.
-    # Restore the previous default until PlatformIO handles this properly.
-    if variant == VARIANT_ESP32P4:
-        add_idf_sdkconfig_option("CONFIG_ESP32P4_SELECTS_REV_LESS_V3", True)
-
     # Set minimum chip revision for ESP32 variant
     # Setting this to 3.0 or higher reduces flash size by excluding workaround code,
     # and for PSRAM users saves significant IRAM by keeping C library functions in ROM.

esphome/components/esp32_ble/__init__.py

@@ -403,21 +403,18 @@ def final_validation(config):
         add_idf_sdkconfig_option("CONFIG_ESP_HOSTED_ENABLE_BT_BLUEDROID", True)
         add_idf_sdkconfig_option("CONFIG_ESP_HOSTED_BLUEDROID_HCI_VHCI", True)
 
+    # Check if BLE Server is needed
+    has_ble_server = "esp32_ble_server" in full_config
+
     # Check if BLE Client is needed (via esp32_ble_tracker or esp32_ble_client)
     has_ble_client = (
         "esp32_ble_tracker" in full_config or "esp32_ble_client" in full_config
     )
 
-    # Always enable GATTS: ESP-IDF 5.5.2.260206 has a bug in gatt_main.c where a
-    # GATT_TRACE_DEBUG references 'msg_len' outside the GATTS_INCLUDED/GATTC_INCLUDED
-    # guard, causing a compile error when both are disabled.
-    # Additionally, when GATT Client is enabled, GATT Server must also be enabled
-    # as an internal dependency in the Bluedroid stack.
+    # ESP-IDF BLE stack requires GATT Server to be enabled when GATT Client is enabled
+    # This is an internal dependency in the Bluedroid stack (tested ESP-IDF 5.4.2-5.5.1)
     # See: https://github.com/espressif/esp-idf/issues/17724
-    # TODO: Revert to conditional once the gatt_main.c bug is fixed upstream:
-    #   has_ble_server = "esp32_ble_server" in full_config
-    #   add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", has_ble_server or has_ble_client)
-    add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", True)
+    add_idf_sdkconfig_option("CONFIG_BT_GATTS_ENABLE", has_ble_server or has_ble_client)
     add_idf_sdkconfig_option("CONFIG_BT_GATTC_ENABLE", has_ble_client)
 
     # Handle max_connections: check for deprecated location in esp32_ble_tracker

esphome/components/ethernet/ethernet_component.h

@@ -110,6 +110,8 @@ class EthernetComponent : public Component {
   const char *get_use_address() const;
   void set_use_address(const char *use_address);
   void get_eth_mac_address_raw(uint8_t *mac);
+  // Remove before 2026.9.0
+  ESPDEPRECATED("Use get_eth_mac_address_pretty_into_buffer() instead. Removed in 2026.9.0", "2026.3.0")
   std::string get_eth_mac_address_pretty();
   const char *get_eth_mac_address_pretty_into_buffer(std::span<char, MAC_ADDRESS_PRETTY_BUFFER_SIZE> buf);
   eth_duplex_t get_duplex_mode();

esphome/components/online_image/__init__.py

@@ -2,97 +2,34 @@ import logging
 
 from esphome import automation
 import esphome.codegen as cg
-from esphome.components.const import CONF_BYTE_ORDER, CONF_REQUEST_HEADERS
+from esphome.components import runtime_image
+from esphome.components.const import CONF_REQUEST_HEADERS
 from esphome.components.http_request import CONF_HTTP_REQUEST_ID, HttpRequestComponent
-from esphome.components.image import (
-    CONF_INVERT_ALPHA,
-    CONF_TRANSPARENCY,
-    IMAGE_SCHEMA,
-    Image_,
-    get_image_type_enum,
-    get_transparency_enum,
-    validate_settings,
-)
 import esphome.config_validation as cv
 from esphome.const import (
     CONF_BUFFER_SIZE,
-    CONF_DITHER,
-    CONF_FILE,
-    CONF_FORMAT,
     CONF_ID,
     CONF_ON_ERROR,
-    CONF_RESIZE,
     CONF_TRIGGER_ID,
-    CONF_TYPE,
     CONF_URL,
 )
 from esphome.core import Lambda
 
-AUTO_LOAD = ["image"]
+AUTO_LOAD = ["image", "runtime_image"]
 DEPENDENCIES = ["display", "http_request"]
 CODEOWNERS = ["@guillempages", "@clydebarrow"]
 MULTI_CONF = True
 
 CONF_ON_DOWNLOAD_FINISHED = "on_download_finished"
-CONF_PLACEHOLDER = "placeholder"
 CONF_UPDATE = "update"
 
 _LOGGER = logging.getLogger(__name__)
 
 online_image_ns = cg.esphome_ns.namespace("online_image")
 
-ImageFormat = online_image_ns.enum("ImageFormat")
-
-
-class Format:
-    def __init__(self, image_type):
-        self.image_type = image_type
-
-    @property
-    def enum(self):
-        return getattr(ImageFormat, self.image_type)
-
-    def actions(self):
-        pass
-
-
-class BMPFormat(Format):
-    def __init__(self):
-        super().__init__("BMP")
-
-    def actions(self):
-        cg.add_define("USE_ONLINE_IMAGE_BMP_SUPPORT")
-
-
-class JPEGFormat(Format):
-    def __init__(self):
-        super().__init__("JPEG")
-
-    def actions(self):
-        cg.add_define("USE_ONLINE_IMAGE_JPEG_SUPPORT")
-        cg.add_library("JPEGDEC", None, "https://github.com/bitbank2/JPEGDEC#ca1e0f2")
-
-
-class PNGFormat(Format):
-    def __init__(self):
-        super().__init__("PNG")
-
-    def actions(self):
-        cg.add_define("USE_ONLINE_IMAGE_PNG_SUPPORT")
-        cg.add_library("pngle", "1.1.0")
-
-
-IMAGE_FORMATS = {
-    x.image_type: x
-    for x in (
-        BMPFormat(),
-        JPEGFormat(),
-        PNGFormat(),
-    )
-}
-IMAGE_FORMATS.update({"JPG": IMAGE_FORMATS["JPEG"]})
-
-OnlineImage = online_image_ns.class_("OnlineImage", cg.PollingComponent, Image_)
+OnlineImage = online_image_ns.class_(
+    "OnlineImage", cg.PollingComponent, runtime_image.RuntimeImage
+)
 
 # Actions
 SetUrlAction = online_image_ns.class_(
@@ -111,29 +48,17 @@ DownloadErrorTrigger = online_image_ns.class_(
 )
 
 
-def remove_options(*options):
-    return {
-        cv.Optional(option): cv.invalid(
-            f"{option} is an invalid option for online_image"
-        )
-        for option in options
-    }
-
-
 ONLINE_IMAGE_SCHEMA = (
-    IMAGE_SCHEMA.extend(remove_options(CONF_FILE, CONF_INVERT_ALPHA, CONF_DITHER))
+    runtime_image.runtime_image_schema(OnlineImage)
     .extend(
         {
-            cv.Required(CONF_ID): cv.declare_id(OnlineImage),
-            cv.GenerateID(CONF_HTTP_REQUEST_ID): cv.use_id(HttpRequestComponent),
             # Online Image specific options
+            cv.GenerateID(CONF_HTTP_REQUEST_ID): cv.use_id(HttpRequestComponent),
             cv.Required(CONF_URL): cv.url,
+            cv.Optional(CONF_BUFFER_SIZE, default=65536): cv.int_range(256, 65536),
             cv.Optional(CONF_REQUEST_HEADERS): cv.All(
                 cv.Schema({cv.string: cv.templatable(cv.string)})
             ),
-            cv.Required(CONF_FORMAT): cv.one_of(*IMAGE_FORMATS, upper=True),
-            cv.Optional(CONF_PLACEHOLDER): cv.use_id(Image_),
-            cv.Optional(CONF_BUFFER_SIZE, default=65536): cv.int_range(256, 65536),
             cv.Optional(CONF_ON_DOWNLOAD_FINISHED): automation.validate_automation(
                 {
                     cv.GenerateID(CONF_TRIGGER_ID): cv.declare_id(
@@ -162,7 +87,7 @@ CONFIG_SCHEMA = cv.Schema(
             rp2040_arduino=cv.Version(0, 0, 0),
             host=cv.Version(0, 0, 0),
         ),
-        validate_settings,
+        runtime_image.validate_runtime_image_settings,
     )
 )
 
@@ -199,23 +124,21 @@ async def online_image_action_to_code(config, action_id, template_arg, args):
 
 
 async def to_code(config):
-    image_format = IMAGE_FORMATS[config[CONF_FORMAT]]
-    image_format.actions()
+    # Use the enhanced helper function to get all runtime image parameters
+    settings = await runtime_image.process_runtime_image_config(config)
 
     url = config[CONF_URL]
-    width, height = config.get(CONF_RESIZE, (0, 0))
-    transparent = get_transparency_enum(config[CONF_TRANSPARENCY])
-
     var = cg.new_Pvariable(
         config[CONF_ID],
         url,
-        width,
-        height,
-        image_format.enum,
-        get_image_type_enum(config[CONF_TYPE]),
-        transparent,
+        settings.width,
+        settings.height,
+        settings.format_enum,
+        settings.image_type_enum,
+        settings.transparent,
+        settings.placeholder or cg.nullptr,
         config[CONF_BUFFER_SIZE],
-        config.get(CONF_BYTE_ORDER) != "LITTLE_ENDIAN",
+        settings.byte_order_big_endian,
     )
     await cg.register_component(var, config)
     await cg.register_parented(var, config[CONF_HTTP_REQUEST_ID])
@@ -227,10 +150,6 @@ async def to_code(config):
         else:
             cg.add(var.add_request_header(key, value))
 
-    if placeholder_id := config.get(CONF_PLACEHOLDER):
-        placeholder = await cg.get_variable(placeholder_id)
-        cg.add(var.set_placeholder(placeholder))
-
     for conf in config.get(CONF_ON_DOWNLOAD_FINISHED, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(trigger, [(bool, "cached")], conf)

esphome/components/online_image/download_buffer.cpp

@@ -1,29 +1,10 @@
-#include "image_decoder.h"
-#include "online_image.h"
-
+#include "download_buffer.h"
 #include "esphome/core/log.h"
+#include <cstring>
 
-namespace esphome {
-namespace online_image {
+namespace esphome::online_image {
 
-static const char *const TAG = "online_image.decoder";
-
-bool ImageDecoder::set_size(int width, int height) {
-  bool success = this->image_->resize_(width, height) > 0;
-  this->x_scale_ = static_cast<double>(this->image_->buffer_width_) / width;
-  this->y_scale_ = static_cast<double>(this->image_->buffer_height_) / height;
-  return success;
-}
-
-void ImageDecoder::draw(int x, int y, int w, int h, const Color &color) {
-  auto width = std::min(this->image_->buffer_width_, static_cast<int>(std::ceil((x + w) * this->x_scale_)));
-  auto height = std::min(this->image_->buffer_height_, static_cast<int>(std::ceil((y + h) * this->y_scale_)));
-  for (int i = x * this->x_scale_; i < width; i++) {
-    for (int j = y * this->y_scale_; j < height; j++) {
-      this->image_->draw_pixel_(i, j, color);
-    }
-  }
-}
+static const char *const TAG = "online_image.download_buffer";
 
 DownloadBuffer::DownloadBuffer(size_t size) : size_(size) {
   this->buffer_ = this->allocator_.allocate(size);
@@ -43,10 +24,12 @@ uint8_t *DownloadBuffer::data(size_t offset) {
 }
 
 size_t DownloadBuffer::read(size_t len) {
-  this->unread_ -= len;
-  if (this->unread_ > 0) {
-    memmove(this->data(), this->data(len), this->unread_);
+  if (len >= this->unread_) {
+    this->unread_ = 0;
+    return 0;
   }
+  this->unread_ -= len;
+  memmove(this->data(), this->data(len), this->unread_);
   return this->unread_;
 }
 
@@ -69,5 +52,4 @@ size_t DownloadBuffer::resize(size_t size) {
   }
 }
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::online_image

esphome/components/online_image/download_buffer.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include "esphome/core/helpers.h"
+#include <cstddef>
+#include <cstdint>
+
+namespace esphome::online_image {
+
+/**
+ * @brief Buffer for managing downloaded data.
+ *
+ * This class provides a buffer for downloading data with tracking of
+ * unread bytes and dynamic resizing capabilities.
+ */
+class DownloadBuffer {
+ public:
+  DownloadBuffer(size_t size);
+  ~DownloadBuffer() { this->allocator_.deallocate(this->buffer_, this->size_); }
+
+  uint8_t *data(size_t offset = 0);
+  uint8_t *append() { return this->data(this->unread_); }
+
+  size_t unread() const { return this->unread_; }
+  size_t size() const { return this->size_; }
+  size_t free_capacity() const { return this->size_ - this->unread_; }
+
+  size_t read(size_t len);
+  size_t write(size_t len) {
+    this->unread_ += len;
+    return this->unread_;
+  }
+
+  void reset() { this->unread_ = 0; }
+  size_t resize(size_t size);
+
+ protected:
+  RAMAllocator<uint8_t> allocator_{};
+  uint8_t *buffer_;
+  size_t size_;
+  /** Total number of downloaded bytes not yet read. */
+  size_t unread_;
+};
+
+}  // namespace esphome::online_image

esphome/components/online_image/online_image.cpp

@@ -1,6 +1,6 @@
 #include "online_image.h"
-
 #include "esphome/core/log.h"
+#include <algorithm>
 
 static const char *const TAG = "online_image";
 static const char *const ETAG_HEADER_NAME = "etag";
@@ -8,142 +8,82 @@ static const char *const IF_NONE_MATCH_HEADER_NAME = "if-none-match";
 static const char *const LAST_MODIFIED_HEADER_NAME = "last-modified";
 static const char *const IF_MODIFIED_SINCE_HEADER_NAME = "if-modified-since";
 
-#include "image_decoder.h"
+namespace esphome::online_image {
 
-#ifdef USE_ONLINE_IMAGE_BMP_SUPPORT
-#include "bmp_image.h"
-#endif
-#ifdef USE_ONLINE_IMAGE_JPEG_SUPPORT
-#include "jpeg_image.h"
-#endif
-#ifdef USE_ONLINE_IMAGE_PNG_SUPPORT
-#include "png_image.h"
-#endif
-
-namespace esphome {
-namespace online_image {
-
-using image::ImageType;
-
-inline bool is_color_on(const Color &color) {
-  // This produces the most accurate monochrome conversion, but is slightly slower.
-  //  return (0.2125 * color.r + 0.7154 * color.g + 0.0721 * color.b) > 127;
-
-  // Approximation using fast integer computations; produces acceptable results
-  // Equivalent to 0.25 * R + 0.5 * G + 0.25 * B
-  return ((color.r >> 2) + (color.g >> 1) + (color.b >> 2)) & 0x80;
-}
-
-OnlineImage::OnlineImage(const std::string &url, int width, int height, ImageFormat format, ImageType type,
-                         image::Transparency transparency, uint32_t download_buffer_size, bool is_big_endian)
-    : Image(nullptr, 0, 0, type, transparency),
-      buffer_(nullptr),
-      download_buffer_(download_buffer_size),
-      download_buffer_initial_size_(download_buffer_size),
-      format_(format),
-      fixed_width_(width),
-      fixed_height_(height),
-      is_big_endian_(is_big_endian) {
+OnlineImage::OnlineImage(const std::string &url, int width, int height, runtime_image::ImageFormat format,
+                         image::ImageType type, image::Transparency transparency, image::Image *placeholder,
+                         uint32_t buffer_size, bool is_big_endian)
+    : RuntimeImage(format, type, transparency, placeholder, is_big_endian, width, height),
+      download_buffer_(buffer_size),
+      download_buffer_initial_size_(buffer_size) {
   this->set_url(url);
 }
 
-void OnlineImage::draw(int x, int y, display::Display *display, Color color_on, Color color_off) {
-  if (this->data_start_) {
-    Image::draw(x, y, display, color_on, color_off);
-  } else if (this->placeholder_) {
-    this->placeholder_->draw(x, y, display, color_on, color_off);
+bool OnlineImage::validate_url_(const std::string &url) {
+  if (url.empty()) {
+    ESP_LOGE(TAG, "URL is empty");
+    return false;
   }
-}
-
-void OnlineImage::release() {
-  if (this->buffer_) {
-    ESP_LOGV(TAG, "Deallocating old buffer");
-    this->allocator_.deallocate(this->buffer_, this->get_buffer_size_());
-    this->data_start_ = nullptr;
-    this->buffer_ = nullptr;
-    this->width_ = 0;
-    this->height_ = 0;
-    this->buffer_width_ = 0;
-    this->buffer_height_ = 0;
-    this->last_modified_ = "";
-    this->etag_ = "";
-    this->end_connection_();
+  if (url.length() > 2048) {
+    ESP_LOGE(TAG, "URL is too long");
+    return false;
   }
-}
-
-size_t OnlineImage::resize_(int width_in, int height_in) {
-  int width = this->fixed_width_;
-  int height = this->fixed_height_;
-  if (this->is_auto_resize_()) {
-    width = width_in;
-    height = height_in;
-    if (this->width_ != width && this->height_ != height) {
-      this->release();
-    }
+  if (url.compare(0, 7, "http://") != 0 && url.compare(0, 8, "https://") != 0) {
+    ESP_LOGE(TAG, "URL must start with http:// or https://");
+    return false;
   }
-  size_t new_size = this->get_buffer_size_(width, height);
-  if (this->buffer_) {
-    // Buffer already allocated => no need to resize
-    return new_size;
-  }
-  ESP_LOGD(TAG, "Allocating new buffer of %zu bytes", new_size);
-  this->buffer_ = this->allocator_.allocate(new_size);
-  if (this->buffer_ == nullptr) {
-    ESP_LOGE(TAG, "allocation of %zu bytes failed. Biggest block in heap: %zu Bytes", new_size,
-             this->allocator_.get_max_free_block_size());
-    this->end_connection_();
-    return 0;
-  }
-  this->buffer_width_ = width;
-  this->buffer_height_ = height;
-  this->width_ = width;
-  ESP_LOGV(TAG, "New size: (%d, %d)", width, height);
-  return new_size;
+  return true;
 }
 
 void OnlineImage::update() {
-  if (this->decoder_) {
+  if (this->is_decoding()) {
     ESP_LOGW(TAG, "Image already being updated.");
     return;
   }
-  ESP_LOGI(TAG, "Updating image %s", this->url_.c_str());
 
-  std::list<http_request::Header> headers = {};
-
-  http_request::Header accept_header;
-  accept_header.name = "Accept";
-  std::string accept_mime_type;
-  switch (this->format_) {
-#ifdef USE_ONLINE_IMAGE_BMP_SUPPORT
-    case ImageFormat::BMP:
-      accept_mime_type = "image/bmp";
-      break;
-#endif  // USE_ONLINE_IMAGE_BMP_SUPPORT
-#ifdef USE_ONLINE_IMAGE_JPEG_SUPPORT
-    case ImageFormat::JPEG:
-      accept_mime_type = "image/jpeg";
-      break;
-#endif  // USE_ONLINE_IMAGE_JPEG_SUPPORT
-#ifdef USE_ONLINE_IMAGE_PNG_SUPPORT
-    case ImageFormat::PNG:
-      accept_mime_type = "image/png";
-      break;
-#endif  // USE_ONLINE_IMAGE_PNG_SUPPORT
-    default:
-      accept_mime_type = "image/*";
+  if (!this->validate_url_(this->url_)) {
+    ESP_LOGE(TAG, "Invalid URL: %s", this->url_.c_str());
+    this->download_error_callback_.call();
+    return;
   }
-  accept_header.value = accept_mime_type + ",*/*;q=0.8";
 
+  ESP_LOGD(TAG, "Updating image from %s", this->url_.c_str());
+
+  std::list<http_request::Header> headers;
+
+  // Add caching headers if we have them
   if (!this->etag_.empty()) {
-    headers.push_back(http_request::Header{IF_NONE_MATCH_HEADER_NAME, this->etag_});
+    headers.push_back({IF_NONE_MATCH_HEADER_NAME, this->etag_});
   }
-
   if (!this->last_modified_.empty()) {
-    headers.push_back(http_request::Header{IF_MODIFIED_SINCE_HEADER_NAME, this->last_modified_});
+    headers.push_back({IF_MODIFIED_SINCE_HEADER_NAME, this->last_modified_});
   }
 
-  headers.push_back(accept_header);
+  // Add Accept header based on image format
+  const char *accept_mime_type;
+  switch (this->get_format()) {
+#ifdef USE_RUNTIME_IMAGE_BMP
+    case runtime_image::BMP:
+      accept_mime_type = "image/bmp,*/*;q=0.8";
+      break;
+#endif
+#ifdef USE_RUNTIME_IMAGE_JPEG
+    case runtime_image::JPEG:
+      accept_mime_type = "image/jpeg,*/*;q=0.8";
+      break;
+#endif
+#ifdef USE_RUNTIME_IMAGE_PNG
+    case runtime_image::PNG:
+      accept_mime_type = "image/png,*/*;q=0.8";
+      break;
+#endif
+    default:
+      accept_mime_type = "image/*,*/*;q=0.8";
+      break;
+  }
+  headers.push_back({"Accept", accept_mime_type});
 
+  // User headers last so they can override any of the above
   for (auto &header : this->request_headers_) {
     headers.push_back(http_request::Header{header.first, header.second.value()});
   }
@@ -175,186 +115,117 @@ void OnlineImage::update() {
   ESP_LOGD(TAG, "Starting download");
   size_t total_size = this->downloader_->content_length;
 
-#ifdef USE_ONLINE_IMAGE_BMP_SUPPORT
-  if (this->format_ == ImageFormat::BMP) {
-    ESP_LOGD(TAG, "Allocating BMP decoder");
-    this->decoder_ = make_unique<BmpDecoder>(this);
-    this->enable_loop();
+  // Initialize decoder with the known format
+  if (!this->begin_decode(total_size)) {
+    ESP_LOGE(TAG, "Failed to initialize decoder for format %d", this->get_format());
+    this->end_connection_();
+    this->download_error_callback_.call();
+    return;
   }
-#endif  // USE_ONLINE_IMAGE_BMP_SUPPORT
-#ifdef USE_ONLINE_IMAGE_JPEG_SUPPORT
-  if (this->format_ == ImageFormat::JPEG) {
-    ESP_LOGD(TAG, "Allocating JPEG decoder");
-    this->decoder_ = esphome::make_unique<JpegDecoder>(this);
-    this->enable_loop();
-  }
-#endif  // USE_ONLINE_IMAGE_JPEG_SUPPORT
-#ifdef USE_ONLINE_IMAGE_PNG_SUPPORT
-  if (this->format_ == ImageFormat::PNG) {
-    ESP_LOGD(TAG, "Allocating PNG decoder");
-    this->decoder_ = make_unique<PngDecoder>(this);
-    this->enable_loop();
-  }
-#endif  // USE_ONLINE_IMAGE_PNG_SUPPORT
 
-  if (!this->decoder_) {
-    ESP_LOGE(TAG, "Could not instantiate decoder. Image format unsupported: %d", this->format_);
-    this->end_connection_();
-    this->download_error_callback_.call();
-    return;
-  }
-  auto prepare_result = this->decoder_->prepare(total_size);
-  if (prepare_result < 0) {
-    this->end_connection_();
-    this->download_error_callback_.call();
-    return;
+  // JPEG requires the complete image in the download buffer before decoding
+  if (this->get_format() == runtime_image::JPEG && total_size > this->download_buffer_.size()) {
+    this->download_buffer_.resize(total_size);
   }
+
   ESP_LOGI(TAG, "Downloading image (Size: %zu)", total_size);
   this->start_time_ = ::time(nullptr);
+  this->enable_loop();
 }
 
 void OnlineImage::loop() {
-  if (!this->decoder_) {
+  if (!this->is_decoding()) {
     // Not decoding at the moment => nothing to do.
     this->disable_loop();
     return;
   }
-  if (!this->downloader_ || this->decoder_->is_finished()) {
-    this->data_start_ = buffer_;
-    this->width_ = buffer_width_;
-    this->height_ = buffer_height_;
-    ESP_LOGD(TAG, "Image fully downloaded, read %zu bytes, width/height = %d/%d", this->downloader_->get_bytes_read(),
-             this->width_, this->height_);
-    ESP_LOGD(TAG, "Total time: %" PRIu32 "s", (uint32_t) (::time(nullptr) - this->start_time_));
+
+  if (!this->downloader_) {
+    ESP_LOGE(TAG, "Downloader not instantiated; cannot download");
+    this->end_connection_();
+    this->download_error_callback_.call();
+    return;
+  }
+
+  // Check if download is complete — use decoder's format-specific completion check
+  // to handle both known content-length and chunked transfer encoding
+  if (this->is_decode_finished() || (this->downloader_->content_length > 0 &&
+                                     this->downloader_->get_bytes_read() >= this->downloader_->content_length &&
+                                     this->download_buffer_.unread() == 0)) {
+    // Finalize decoding
+    this->end_decode();
+
+    ESP_LOGD(TAG, "Image fully downloaded, %zu bytes in %" PRIu32 "s", this->downloader_->get_bytes_read(),
+             (uint32_t) (::time(nullptr) - this->start_time_));
+
+    // Save caching headers
     this->etag_ = this->downloader_->get_response_header(ETAG_HEADER_NAME);
     this->last_modified_ = this->downloader_->get_response_header(LAST_MODIFIED_HEADER_NAME);
+
     this->download_finished_callback_.call(false);
     this->end_connection_();
     return;
   }
-  if (this->downloader_ == nullptr) {
-    ESP_LOGE(TAG, "Downloader not instantiated; cannot download");
-    return;
-  }
+
+  // Download and decode more data
   size_t available = this->download_buffer_.free_capacity();
-  if (available) {
-    // Some decoders need to fully download the image before downloading.
-    // In case of huge images, don't wait blocking until the whole image has been downloaded,
-    // use smaller chunks
+  if (available > 0) {
+    // Download in chunks to avoid blocking
     available = std::min(available, this->download_buffer_initial_size_);
     auto len = this->downloader_->read(this->download_buffer_.append(), available);
+
     if (len > 0) {
       this->download_buffer_.write(len);
-      auto fed = this->decoder_->decode(this->download_buffer_.data(), this->download_buffer_.unread());
-      if (fed < 0) {
-        ESP_LOGE(TAG, "Error when decoding image.");
+
+      // Feed data to decoder
+      auto consumed = this->feed_data(this->download_buffer_.data(), this->download_buffer_.unread());
+
+      if (consumed < 0) {
+        ESP_LOGE(TAG, "Error decoding image: %d", consumed);
         this->end_connection_();
         this->download_error_callback_.call();
         return;
       }
-      this->download_buffer_.read(fed);
-    }
-  }
-}
 
-void OnlineImage::map_chroma_key(Color &color) {
-  if (this->transparency_ == image::TRANSPARENCY_CHROMA_KEY) {
-    if (color.g == 1 && color.r == 0 && color.b == 0) {
-      color.g = 0;
-    }
-    if (color.w < 0x80) {
-      color.r = 0;
-      color.g = this->type_ == ImageType::IMAGE_TYPE_RGB565 ? 4 : 1;
-      color.b = 0;
-    }
-  }
-}
-
-void OnlineImage::draw_pixel_(int x, int y, Color color) {
-  if (!this->buffer_) {
-    ESP_LOGE(TAG, "Buffer not allocated!");
-    return;
-  }
-  if (x < 0 || y < 0 || x >= this->buffer_width_ || y >= this->buffer_height_) {
-    ESP_LOGE(TAG, "Tried to paint a pixel (%d,%d) outside the image!", x, y);
-    return;
-  }
-  uint32_t pos = this->get_position_(x, y);
-  switch (this->type_) {
-    case ImageType::IMAGE_TYPE_BINARY: {
-      const uint32_t width_8 = ((this->width_ + 7u) / 8u) * 8u;
-      pos = x + y * width_8;
-      auto bitno = 0x80 >> (pos % 8u);
-      pos /= 8u;
-      auto on = is_color_on(color);
-      if (this->has_transparency() && color.w < 0x80)
-        on = false;
-      if (on) {
-        this->buffer_[pos] |= bitno;
-      } else {
-        this->buffer_[pos] &= ~bitno;
+      if (consumed > 0) {
+        this->download_buffer_.read(consumed);
       }
-      break;
+    } else if (len < 0) {
+      ESP_LOGE(TAG, "Error downloading image: %d", len);
+      this->end_connection_();
+      this->download_error_callback_.call();
+      return;
     }
-    case ImageType::IMAGE_TYPE_GRAYSCALE: {
-      auto gray = static_cast<uint8_t>(0.2125 * color.r + 0.7154 * color.g + 0.0721 * color.b);
-      if (this->transparency_ == image::TRANSPARENCY_CHROMA_KEY) {
-        if (gray == 1) {
-          gray = 0;
-        }
-        if (color.w < 0x80) {
-          gray = 1;
-        }
-      } else if (this->transparency_ == image::TRANSPARENCY_ALPHA_CHANNEL) {
-        if (color.w != 0xFF)
-          gray = color.w;
-      }
-      this->buffer_[pos] = gray;
-      break;
-    }
-    case ImageType::IMAGE_TYPE_RGB565: {
-      this->map_chroma_key(color);
-      uint16_t col565 = display::ColorUtil::color_to_565(color);
-      if (this->is_big_endian_) {
-        this->buffer_[pos + 0] = static_cast<uint8_t>((col565 >> 8) & 0xFF);
-        this->buffer_[pos + 1] = static_cast<uint8_t>(col565 & 0xFF);
-      } else {
-        this->buffer_[pos + 0] = static_cast<uint8_t>(col565 & 0xFF);
-        this->buffer_[pos + 1] = static_cast<uint8_t>((col565 >> 8) & 0xFF);
-      }
-      if (this->transparency_ == image::TRANSPARENCY_ALPHA_CHANNEL) {
-        this->buffer_[pos + 2] = color.w;
-      }
-      break;
-    }
-    case ImageType::IMAGE_TYPE_RGB: {
-      this->map_chroma_key(color);
-      this->buffer_[pos + 0] = color.r;
-      this->buffer_[pos + 1] = color.g;
-      this->buffer_[pos + 2] = color.b;
-      if (this->transparency_ == image::TRANSPARENCY_ALPHA_CHANNEL) {
-        this->buffer_[pos + 3] = color.w;
-      }
-      break;
+  } else {
+    // Buffer is full, need to decode some data first
+    auto consumed = this->feed_data(this->download_buffer_.data(), this->download_buffer_.unread());
+    if (consumed > 0) {
+      this->download_buffer_.read(consumed);
+    } else if (consumed < 0) {
+      ESP_LOGE(TAG, "Decode error with full buffer: %d", consumed);
+      this->end_connection_();
+      this->download_error_callback_.call();
+      return;
+    } else {
+      // Decoder can't process more data, might need complete image
+      // This is normal for JPEG which needs complete data
+      ESP_LOGV(TAG, "Decoder waiting for more data");
     }
   }
 }
 
 void OnlineImage::end_connection_() {
+  // Abort any in-progress decode to free decoder resources.
+  // Use RuntimeImage::release() directly to avoid recursion with OnlineImage::release().
+  if (this->is_decoding()) {
+    RuntimeImage::release();
+  }
   if (this->downloader_) {
     this->downloader_->end();
     this->downloader_ = nullptr;
   }
-  this->decoder_.reset();
   this->download_buffer_.reset();
-}
-
-bool OnlineImage::validate_url_(const std::string &url) {
-  if ((url.length() < 8) || !url.starts_with("http") || (url.find("://") == std::string::npos)) {
-    ESP_LOGE(TAG, "URL is invalid and/or must be prefixed with 'http://' or 'https://'");
-    return false;
-  }
-  return true;
+  this->disable_loop();
 }
 
 void OnlineImage::add_on_finished_callback(std::function<void(bool)> &&callback) {
@@ -365,5 +236,16 @@ void OnlineImage::add_on_error_callback(std::function<void()> &&callback) {
   this->download_error_callback_.add(std::move(callback));
 }
 
-}  // namespace online_image
-}  // namespace esphome
+void OnlineImage::release() {
+  // Clear cache headers
+  this->etag_ = "";
+  this->last_modified_ = "";
+
+  // End any active connection
+  this->end_connection_();
+
+  // Call parent's release to free the image buffer
+  RuntimeImage::release();
+}
+
+}  // namespace esphome::online_image

esphome/components/online_image/online_image.h

@@ -1,15 +1,14 @@
 #pragma once
 
+#include "download_buffer.h"
 #include "esphome/components/http_request/http_request.h"
-#include "esphome/components/image/image.h"
+#include "esphome/components/runtime_image/runtime_image.h"
+#include "esphome/core/automation.h"
 #include "esphome/core/component.h"
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 
-#include "image_decoder.h"
-
-namespace esphome {
-namespace online_image {
+namespace esphome::online_image {
 
 using t_http_codes = enum {
   HTTP_CODE_OK = 200,
@@ -17,27 +16,13 @@ using t_http_codes = enum {
   HTTP_CODE_NOT_FOUND = 404,
 };
 
-/**
- * @brief Format that the image is encoded with.
- */
-enum ImageFormat {
-  /** Automatically detect from MIME type. Not supported yet. */
-  AUTO,
-  /** JPEG format. */
-  JPEG,
-  /** PNG format. */
-  PNG,
-  /** BMP format. */
-  BMP,
-};
-
 /**
  * @brief Download an image from a given URL, and decode it using the specified decoder.
  * The image will then be stored in a buffer, so that it can be re-displayed without the
  * need to re-download or re-decode.
  */
 class OnlineImage : public PollingComponent,
-                    public image::Image,
+                    public runtime_image::RuntimeImage,
                     public Parented<esphome::http_request::HttpRequestComponent> {
  public:
   /**
@@ -46,17 +31,19 @@ class OnlineImage : public PollingComponent,
    * @param url URL to download the image from.
    * @param width Desired width of the target image area.
    * @param height Desired height of the target image area.
-   * @param format Format that the image is encoded in (@see ImageFormat).
+   * @param format Format that the image is encoded in (@see runtime_image::ImageFormat).
+   * @param type The pixel format for the image.
+   * @param transparency The transparency type for the image.
+   * @param placeholder Optional placeholder image to show while loading.
    * @param buffer_size Size of the buffer used to download the image.
+   * @param is_big_endian Whether the image is stored in big-endian format.
    */
-  OnlineImage(const std::string &url, int width, int height, ImageFormat format, image::ImageType type,
-              image::Transparency transparency, uint32_t buffer_size, bool is_big_endian);
-
-  void draw(int x, int y, display::Display *display, Color color_on, Color color_off) override;
+  OnlineImage(const std::string &url, int width, int height, runtime_image::ImageFormat format, image::ImageType type,
+              image::Transparency transparency, image::Image *placeholder, uint32_t buffer_size,
+              bool is_big_endian = false);
 
   void update() override;
   void loop() override;
-  void map_chroma_key(Color &color);
 
   /** Set the URL to download the image from. */
   void set_url(const std::string &url) {
@@ -69,82 +56,26 @@ class OnlineImage : public PollingComponent,
 
   /** Add the request header */
   template<typename V> void add_request_header(const std::string &header, V value) {
-    this->request_headers_.push_back(std::pair<std::string, TemplatableValue<std::string> >(header, value));
+    this->request_headers_.push_back(std::pair<std::string, TemplatableValue<std::string>>(header, value));
   }
 
-  /**
-   * @brief Set the image that needs to be shown as long as the downloaded image
-   *  is not available.
-   *
-   * @param placeholder Pointer to the (@link Image) to show as placeholder.
-   */
-  void set_placeholder(image::Image *placeholder) { this->placeholder_ = placeholder; }
-
   /**
    * Release the buffer storing the image. The image will need to be downloaded again
    * to be able to be displayed.
    */
   void release();
 
-  /**
-   * Resize the download buffer
-   *
-   * @param size The new size for the download buffer.
-   */
-  size_t resize_download_buffer(size_t size) { return this->download_buffer_.resize(size); }
-
   void add_on_finished_callback(std::function<void(bool)> &&callback);
   void add_on_error_callback(std::function<void()> &&callback);
 
  protected:
   bool validate_url_(const std::string &url);
-
-  RAMAllocator<uint8_t> allocator_{};
-
-  uint32_t get_buffer_size_() const { return get_buffer_size_(this->buffer_width_, this->buffer_height_); }
-  int get_buffer_size_(int width, int height) const { return (this->get_bpp() * width + 7u) / 8u * height; }
-
-  int get_position_(int x, int y) const { return (x + y * this->buffer_width_) * this->get_bpp() / 8; }
-
-  ESPHOME_ALWAYS_INLINE bool is_auto_resize_() const { return this->fixed_width_ == 0 || this->fixed_height_ == 0; }
-
-  /**
-   * @brief Resize the image buffer to the requested dimensions.
-   *
-   * The buffer will be allocated if not existing.
-   * If the dimensions have been fixed in the yaml config, the buffer will be created
-   * with those dimensions and not resized, even on request.
-   * Otherwise, the old buffer will be deallocated and a new buffer with the requested
-   * allocated
-   *
-   * @param width
-   * @param height
-   * @return 0 if no memory could be allocated, the size of the new buffer otherwise.
-   */
-  size_t resize_(int width, int height);
-
-  /**
-   * @brief Draw a pixel into the buffer.
-   *
-   * This is used by the decoder to fill the buffer that will later be displayed
-   * by the `draw` method. This will internally convert the supplied 32 bit RGBA
-   * color into the requested image storage format.
-   *
-   * @param x Horizontal pixel position.
-   * @param y Vertical pixel position.
-   * @param color 32 bit color to put into the pixel.
-   */
-  void draw_pixel_(int x, int y, Color color);
-
   void end_connection_();
 
   CallbackManager<void(bool)> download_finished_callback_{};
   CallbackManager<void()> download_error_callback_{};
 
   std::shared_ptr<http_request::HttpContainer> downloader_{nullptr};
-  std::unique_ptr<ImageDecoder> decoder_{nullptr};
-
-  uint8_t *buffer_;
   DownloadBuffer download_buffer_;
   /**
    * This is the *initial* size of the download buffer, not the current size.
@@ -153,40 +84,10 @@ class OnlineImage : public PollingComponent,
    */
   size_t download_buffer_initial_size_;
 
-  const ImageFormat format_;
-  image::Image *placeholder_{nullptr};
-
   std::string url_{""};
 
-  std::vector<std::pair<std::string, TemplatableValue<std::string> > > request_headers_;
+  std::vector<std::pair<std::string, TemplatableValue<std::string>>> request_headers_;
 
-  /** width requested on configuration, or 0 if non specified. */
-  const int fixed_width_;
-  /** height requested on configuration, or 0 if non specified. */
-  const int fixed_height_;
-  /**
-   * Whether the image is stored in big-endian format.
-   * This is used to determine how to store 16 bit colors in the buffer.
-   */
-  bool is_big_endian_;
-  /**
-   * Actual width of the current image. If fixed_width_ is specified,
-   * this will be equal to it; otherwise it will be set once the decoding
-   * starts and the original size is known.
-   * This needs to be separate from "BaseImage::get_width()" because the latter
-   * must return 0 until the image has been decoded (to avoid showing partially
-   * decoded images).
-   */
-  int buffer_width_;
-  /**
-   * Actual height of the current image. If fixed_height_ is specified,
-   * this will be equal to it; otherwise it will be set once the decoding
-   * starts and the original size is known.
-   * This needs to be separate from "BaseImage::get_height()" because the latter
-   * must return 0 until the image has been decoded (to avoid showing partially
-   * decoded images).
-   */
-  int buffer_height_;
   /**
    * The value of the ETag HTTP header provided in the last response.
    */
@@ -197,9 +98,6 @@ class OnlineImage : public PollingComponent,
   std::string last_modified_ = "";
 
   time_t start_time_;
-
-  friend bool ImageDecoder::set_size(int width, int height);
-  friend void ImageDecoder::draw(int x, int y, int w, int h, const Color &color);
 };
 
 template<typename... Ts> class OnlineImageSetUrlAction : public Action<Ts...> {
@@ -241,5 +139,4 @@ class DownloadErrorTrigger : public Trigger<> {
   }
 };
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::online_image

esphome/components/pulse_meter/pulse_meter_sensor.cpp

@@ -38,8 +38,7 @@ void PulseMeterSensor::setup() {
 }
 
 void PulseMeterSensor::loop() {
-  // Reset the count in get before we pass it back to the ISR as set
-  this->get_->count_ = 0;
+  State state;
 
   {
     // Lock the interrupt so the interrupt code doesn't interfere with itself
@@ -58,31 +57,35 @@ void PulseMeterSensor::loop() {
     }
     this->last_pin_val_ = current;
 
-    // Swap out set and get to get the latest state from the ISR
-    std::swap(this->set_, this->get_);
+    // Get the latest state from the ISR and reset the count in the ISR
+    state.last_detected_edge_us_ = this->state_.last_detected_edge_us_;
+    state.last_rising_edge_us_ = this->state_.last_rising_edge_us_;
+    state.count_ = this->state_.count_;
+    this->state_.count_ = 0;
   }
 
   const uint32_t now = micros();
 
   // If an edge was peeked, repay the debt
-  if (this->peeked_edge_ && this->get_->count_ > 0) {
+  if (this->peeked_edge_ && state.count_ > 0) {
     this->peeked_edge_ = false;
-    this->get_->count_--;  // NOLINT(clang-diagnostic-deprecated-volatile)
+    state.count_--;
   }
 
-  // If there is an unprocessed edge, and filter_us_ has passed since, count this edge early
-  if (this->get_->last_rising_edge_us_ != this->get_->last_detected_edge_us_ &&
-      now - this->get_->last_rising_edge_us_ >= this->filter_us_) {
+  // If there is an unprocessed edge, and filter_us_ has passed since, count this edge early.
+  // Wait for the debt to be repaid before counting another unprocessed edge early.
+  if (!this->peeked_edge_ && state.last_rising_edge_us_ != state.last_detected_edge_us_ &&
+      now - state.last_rising_edge_us_ >= this->filter_us_) {
     this->peeked_edge_ = true;
-    this->get_->last_detected_edge_us_ = this->get_->last_rising_edge_us_;
-    this->get_->count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
+    state.last_detected_edge_us_ = state.last_rising_edge_us_;
+    state.count_++;
   }
 
   // Check if we detected a pulse this loop
-  if (this->get_->count_ > 0) {
+  if (state.count_ > 0) {
     // Keep a running total of pulses if a total sensor is configured
     if (this->total_sensor_ != nullptr) {
-      this->total_pulses_ += this->get_->count_;
+      this->total_pulses_ += state.count_;
       const uint32_t total = this->total_pulses_;
       this->total_sensor_->publish_state(total);
     }
@@ -94,15 +97,15 @@ void PulseMeterSensor::loop() {
         this->meter_state_ = MeterState::RUNNING;
       } break;
       case MeterState::RUNNING: {
-        uint32_t delta_us = this->get_->last_detected_edge_us_ - this->last_processed_edge_us_;
-        float pulse_width_us = delta_us / float(this->get_->count_);
-        ESP_LOGV(TAG, "New pulse, delta: %" PRIu32 " µs, count: %" PRIu32 ", width: %.5f µs", delta_us,
-                 this->get_->count_, pulse_width_us);
+        uint32_t delta_us = state.last_detected_edge_us_ - this->last_processed_edge_us_;
+        float pulse_width_us = delta_us / float(state.count_);
+        ESP_LOGV(TAG, "New pulse, delta: %" PRIu32 " µs, count: %" PRIu32 ", width: %.5f µs", delta_us, state.count_,
+                 pulse_width_us);
         this->publish_state((60.0f * 1000000.0f) / pulse_width_us);
       } break;
     }
 
-    this->last_processed_edge_us_ = this->get_->last_detected_edge_us_;
+    this->last_processed_edge_us_ = state.last_detected_edge_us_;
   }
   // No detected edges this loop
   else {
@@ -141,14 +144,14 @@ void IRAM_ATTR PulseMeterSensor::edge_intr(PulseMeterSensor *sensor) {
   // This is an interrupt handler - we can't call any virtual method from this method
   // Get the current time before we do anything else so the measurements are consistent
   const uint32_t now = micros();
-  auto &state = sensor->edge_state_;
-  auto &set = *sensor->set_;
+  auto &edge_state = sensor->edge_state_;
+  auto &state = sensor->state_;
 
-  if ((now - state.last_sent_edge_us_) >= sensor->filter_us_) {
-    state.last_sent_edge_us_ = now;
-    set.last_detected_edge_us_ = now;
-    set.last_rising_edge_us_ = now;
-    set.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
+  if ((now - edge_state.last_sent_edge_us_) >= sensor->filter_us_) {
+    edge_state.last_sent_edge_us_ = now;
+    state.last_detected_edge_us_ = now;
+    state.last_rising_edge_us_ = now;
+    state.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
   }
 
   // This ISR is bound to rising edges, so the pin is high
@@ -160,26 +163,26 @@ void IRAM_ATTR PulseMeterSensor::pulse_intr(PulseMeterSensor *sensor) {
   // Get the current time before we do anything else so the measurements are consistent
   const uint32_t now = micros();
   const bool pin_val = sensor->isr_pin_.digital_read();
-  auto &state = sensor->pulse_state_;
-  auto &set = *sensor->set_;
+  auto &pulse_state = sensor->pulse_state_;
+  auto &state = sensor->state_;
 
   // Filter length has passed since the last interrupt
-  const bool length = now - state.last_intr_ >= sensor->filter_us_;
+  const bool length = now - pulse_state.last_intr_ >= sensor->filter_us_;
 
-  if (length && state.latched_ && !sensor->last_pin_val_) {  // Long enough low edge
-    state.latched_ = false;
-  } else if (length && !state.latched_ && sensor->last_pin_val_) {  // Long enough high edge
-    state.latched_ = true;
-    set.last_detected_edge_us_ = state.last_intr_;
-    set.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
+  if (length && pulse_state.latched_ && !sensor->last_pin_val_) {  // Long enough low edge
+    pulse_state.latched_ = false;
+  } else if (length && !pulse_state.latched_ && sensor->last_pin_val_) {  // Long enough high edge
+    pulse_state.latched_ = true;
+    state.last_detected_edge_us_ = pulse_state.last_intr_;
+    state.count_++;  // NOLINT(clang-diagnostic-deprecated-volatile)
   }
 
   // Due to order of operations this includes
   //    length && latched && rising   (just reset from a long low edge)
   //    !latched && (rising || high)  (noise on the line resetting the potential rising edge)
-  set.last_rising_edge_us_ = !state.latched_ && pin_val ? now : set.last_detected_edge_us_;
+  state.last_rising_edge_us_ = !pulse_state.latched_ && pin_val ? now : state.last_detected_edge_us_;
 
-  state.last_intr_ = now;
+  pulse_state.last_intr_ = now;
   sensor->last_pin_val_ = pin_val;
 }
 

esphome/components/pulse_meter/pulse_meter_sensor.h

@@ -46,17 +46,16 @@ class PulseMeterSensor : public sensor::Sensor, public Component {
   uint32_t total_pulses_ = 0;
   uint32_t last_processed_edge_us_ = 0;
 
-  // This struct (and the two pointers) are used to pass data between the ISR and loop.
-  // These two pointers are exchanged each loop.
-  // Use these to send data from the ISR to the loop not the other way around (except for resetting the values).
+  // This struct and variable are used to pass data between the ISR and loop.
+  // The data from state_ is read and then count_ in state_ is reset in each loop.
+  // This must be done while guarded by an InterruptLock. Use this variable to send data
+  // from the ISR to the loop not the other way around (except for resetting count_).
   struct State {
     uint32_t last_detected_edge_us_ = 0;
     uint32_t last_rising_edge_us_ = 0;
     uint32_t count_ = 0;
   };
-  State state_[2];
-  volatile State *set_ = state_;
-  volatile State *get_ = state_ + 1;
+  volatile State state_{};
 
   // Only use the following variables in the ISR or while guarded by an InterruptLock
   ISRInternalGPIOPin isr_pin_;

esphome/components/runtime_image/__init__.py

@@ -0,0 +1,191 @@
+from dataclasses import dataclass
+
+import esphome.codegen as cg
+from esphome.components.const import CONF_BYTE_ORDER
+from esphome.components.image import (
+    IMAGE_TYPE,
+    Image_,
+    validate_settings,
+    validate_transparency,
+    validate_type,
+)
+import esphome.config_validation as cv
+from esphome.const import CONF_FORMAT, CONF_ID, CONF_RESIZE, CONF_TYPE
+
+AUTO_LOAD = ["image"]
+CODEOWNERS = ["@guillempages", "@clydebarrow", "@kahrendt"]
+
+CONF_PLACEHOLDER = "placeholder"
+CONF_TRANSPARENCY = "transparency"
+
+runtime_image_ns = cg.esphome_ns.namespace("runtime_image")
+
+# Base decoder classes
+ImageDecoder = runtime_image_ns.class_("ImageDecoder")
+BmpDecoder = runtime_image_ns.class_("BmpDecoder", ImageDecoder)
+JpegDecoder = runtime_image_ns.class_("JpegDecoder", ImageDecoder)
+PngDecoder = runtime_image_ns.class_("PngDecoder", ImageDecoder)
+
+# Runtime image class
+RuntimeImage = runtime_image_ns.class_(
+    "RuntimeImage", cg.esphome_ns.namespace("image").class_("Image")
+)
+
+# Image format enum
+ImageFormat = runtime_image_ns.enum("ImageFormat")
+IMAGE_FORMAT_AUTO = ImageFormat.AUTO
+IMAGE_FORMAT_JPEG = ImageFormat.JPEG
+IMAGE_FORMAT_PNG = ImageFormat.PNG
+IMAGE_FORMAT_BMP = ImageFormat.BMP
+
+# Export enum for decode errors
+DecodeError = runtime_image_ns.enum("DecodeError")
+DECODE_ERROR_INVALID_TYPE = DecodeError.DECODE_ERROR_INVALID_TYPE
+DECODE_ERROR_UNSUPPORTED_FORMAT = DecodeError.DECODE_ERROR_UNSUPPORTED_FORMAT
+DECODE_ERROR_OUT_OF_MEMORY = DecodeError.DECODE_ERROR_OUT_OF_MEMORY
+
+
+class Format:
+    """Base class for image format definitions."""
+
+    def __init__(self, name: str, decoder_class: cg.MockObjClass) -> None:
+        self.name = name
+        self.decoder_class = decoder_class
+
+    def actions(self) -> None:
+        """Add defines and libraries needed for this format."""
+
+
+class BMPFormat(Format):
+    """BMP format decoder configuration."""
+
+    def __init__(self):
+        super().__init__("BMP", BmpDecoder)
+
+    def actions(self) -> None:
+        cg.add_define("USE_RUNTIME_IMAGE_BMP")
+
+
+class JPEGFormat(Format):
+    """JPEG format decoder configuration."""
+
+    def __init__(self):
+        super().__init__("JPEG", JpegDecoder)
+
+    def actions(self) -> None:
+        cg.add_define("USE_RUNTIME_IMAGE_JPEG")
+        cg.add_library("JPEGDEC", None, "https://github.com/bitbank2/JPEGDEC#ca1e0f2")
+
+
+class PNGFormat(Format):
+    """PNG format decoder configuration."""
+
+    def __init__(self):
+        super().__init__("PNG", PngDecoder)
+
+    def actions(self) -> None:
+        cg.add_define("USE_RUNTIME_IMAGE_PNG")
+        cg.add_library("pngle", "1.1.0")
+
+
+# Registry of available formats
+IMAGE_FORMATS = {
+    "BMP": BMPFormat(),
+    "JPEG": JPEGFormat(),
+    "PNG": PNGFormat(),
+    "JPG": JPEGFormat(),  # Alias for JPEG
+}
+
+
+def get_format(format_name: str) -> Format | None:
+    """Get a format instance by name."""
+    return IMAGE_FORMATS.get(format_name.upper())
+
+
+def enable_format(format_name: str) -> Format | None:
+    """Enable a specific image format by adding its defines and libraries."""
+    format_obj = get_format(format_name)
+    if format_obj:
+        format_obj.actions()
+        return format_obj
+    return None
+
+
+# Runtime image configuration schema base - to be extended by components
+def runtime_image_schema(image_class: cg.MockObjClass = RuntimeImage) -> cv.Schema:
+    """Create a runtime image schema with the specified image class."""
+    return cv.Schema(
+        {
+            cv.Required(CONF_ID): cv.declare_id(image_class),
+            cv.Required(CONF_FORMAT): cv.one_of(*IMAGE_FORMATS, upper=True),
+            cv.Optional(CONF_RESIZE): cv.dimensions,
+            cv.Required(CONF_TYPE): validate_type(IMAGE_TYPE),
+            cv.Optional(CONF_BYTE_ORDER): cv.one_of(
+                "BIG_ENDIAN", "LITTLE_ENDIAN", upper=True
+            ),
+            cv.Optional(CONF_TRANSPARENCY, default="OPAQUE"): validate_transparency(),
+            cv.Optional(CONF_PLACEHOLDER): cv.use_id(Image_),
+        }
+    )
+
+
+def validate_runtime_image_settings(config: dict) -> dict:
+    """Apply validate_settings from image component to runtime image config."""
+    return validate_settings(config)
+
+
+@dataclass
+class RuntimeImageSettings:
+    """Processed runtime image configuration parameters."""
+
+    width: int
+    height: int
+    format_enum: cg.MockObj
+    image_type_enum: cg.MockObj
+    transparent: cg.MockObj
+    byte_order_big_endian: bool
+    placeholder: cg.MockObj | None
+
+
+async def process_runtime_image_config(config: dict) -> RuntimeImageSettings:
+    """
+    Helper function to process common runtime image configuration parameters.
+    Handles format enabling and returns all necessary enums and parameters.
+    """
+    from esphome.components.image import get_image_type_enum, get_transparency_enum
+
+    # Get resize dimensions with default (0, 0)
+    width, height = config.get(CONF_RESIZE, (0, 0))
+
+    # Handle format (required for runtime images)
+    format_name = config[CONF_FORMAT]
+    # Enable the format in the runtime_image component
+    enable_format(format_name)
+    # Map format names to enum values (handle JPG as alias for JPEG)
+    if format_name.upper() == "JPG":
+        format_name = "JPEG"
+    format_enum = getattr(ImageFormat, format_name.upper())
+
+    # Get image type enum
+    image_type_enum = get_image_type_enum(config[CONF_TYPE])
+
+    # Get transparency enum
+    transparent = get_transparency_enum(config.get(CONF_TRANSPARENCY, "OPAQUE"))
+
+    # Get byte order (True for big endian, False for little endian)
+    byte_order_big_endian = config.get(CONF_BYTE_ORDER) != "LITTLE_ENDIAN"
+
+    # Get placeholder if specified
+    placeholder = None
+    if placeholder_id := config.get(CONF_PLACEHOLDER):
+        placeholder = await cg.get_variable(placeholder_id)
+
+    return RuntimeImageSettings(
+        width=width,
+        height=height,
+        format_enum=format_enum,
+        image_type_enum=image_type_enum,
+        transparent=transparent,
+        byte_order_big_endian=byte_order_big_endian,
+        placeholder=placeholder,
+    )

esphome/components/runtime_image/bmp_decoder.cpp

@@ -1,15 +1,14 @@
-#include "bmp_image.h"
+#include "bmp_decoder.h"
 
-#ifdef USE_ONLINE_IMAGE_BMP_SUPPORT
+#ifdef USE_RUNTIME_IMAGE_BMP
 
 #include "esphome/components/display/display.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-namespace esphome {
-namespace online_image {
+namespace esphome::runtime_image {
 
-static const char *const TAG = "online_image.bmp";
+static const char *const TAG = "image_decoder.bmp";
 
 int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
   size_t index = 0;
@@ -30,7 +29,11 @@ int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
       return DECODE_ERROR_INVALID_TYPE;
     }
 
-    this->download_size_ = encode_uint32(buffer[5], buffer[4], buffer[3], buffer[2]);
+    // BMP file contains its own size in the header
+    size_t file_size = encode_uint32(buffer[5], buffer[4], buffer[3], buffer[2]);
+    if (this->expected_size_ == 0) {
+      this->expected_size_ = file_size;  // Use file header size if not provided
+    }
     this->data_offset_ = encode_uint32(buffer[13], buffer[12], buffer[11], buffer[10]);
 
     this->current_index_ = 14;
@@ -90,8 +93,8 @@ int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
       while (index < size) {
         uint8_t current_byte = buffer[index];
         for (uint8_t i = 0; i < 8; i++) {
-          size_t x = (this->paint_index_ % this->width_) + i;
-          size_t y = (this->height_ - 1) - (this->paint_index_ / this->width_);
+          size_t x = (this->paint_index_ % static_cast<size_t>(this->width_)) + i;
+          size_t y = static_cast<size_t>(this->height_ - 1) - (this->paint_index_ / static_cast<size_t>(this->width_));
           Color c = (current_byte & (1 << (7 - i))) ? display::COLOR_ON : display::COLOR_OFF;
           this->draw(x, y, 1, 1, c);
         }
@@ -110,8 +113,8 @@ int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
         uint8_t b = buffer[index];
         uint8_t g = buffer[index + 1];
         uint8_t r = buffer[index + 2];
-        size_t x = this->paint_index_ % this->width_;
-        size_t y = (this->height_ - 1) - (this->paint_index_ / this->width_);
+        size_t x = this->paint_index_ % static_cast<size_t>(this->width_);
+        size_t y = static_cast<size_t>(this->height_ - 1) - (this->paint_index_ / static_cast<size_t>(this->width_));
         Color c = Color(r, g, b);
         this->draw(x, y, 1, 1, c);
         this->paint_index_++;
@@ -133,7 +136,6 @@ int HOT BmpDecoder::decode(uint8_t *buffer, size_t size) {
   return size;
 };
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image
 
-#endif  // USE_ONLINE_IMAGE_BMP_SUPPORT
+#endif  // USE_RUNTIME_IMAGE_BMP

esphome/components/runtime_image/bmp_decoder.h

@@ -1,27 +1,32 @@
 #pragma once
 
 #include "esphome/core/defines.h"
-#ifdef USE_ONLINE_IMAGE_BMP_SUPPORT
+#ifdef USE_RUNTIME_IMAGE_BMP
 
 #include "image_decoder.h"
+#include "runtime_image.h"
 
-namespace esphome {
-namespace online_image {
+namespace esphome::runtime_image {
 
 /**
- * @brief Image decoder specialization for PNG images.
+ * @brief Image decoder specialization for BMP images.
  */
 class BmpDecoder : public ImageDecoder {
  public:
   /**
    * @brief Construct a new BMP Decoder object.
    *
-   * @param display The image to decode the stream into.
+   * @param image The RuntimeImage to decode the stream into.
    */
-  BmpDecoder(OnlineImage *image) : ImageDecoder(image) {}
+  BmpDecoder(RuntimeImage *image) : ImageDecoder(image) {}
 
   int HOT decode(uint8_t *buffer, size_t size) override;
 
+  bool is_finished() const override {
+    // BMP is finished when we've decoded all pixel data
+    return this->paint_index_ >= static_cast<size_t>(this->width_ * this->height_);
+  }
+
  protected:
   size_t current_index_{0};
   size_t paint_index_{0};
@@ -36,7 +41,6 @@ class BmpDecoder : public ImageDecoder {
   uint8_t padding_bytes_{0};
 };
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image
 
-#endif  // USE_ONLINE_IMAGE_BMP_SUPPORT
+#endif  // USE_RUNTIME_IMAGE_BMP

esphome/components/runtime_image/image_decoder.cpp

@@ -0,0 +1,28 @@
+#include "image_decoder.h"
+#include "runtime_image.h"
+#include "esphome/core/log.h"
+#include <algorithm>
+#include <cmath>
+
+namespace esphome::runtime_image {
+
+static const char *const TAG = "image_decoder";
+
+bool ImageDecoder::set_size(int width, int height) {
+  bool success = this->image_->resize(width, height) > 0;
+  this->x_scale_ = static_cast<double>(this->image_->get_buffer_width()) / width;
+  this->y_scale_ = static_cast<double>(this->image_->get_buffer_height()) / height;
+  return success;
+}
+
+void ImageDecoder::draw(int x, int y, int w, int h, const Color &color) {
+  auto width = std::min(this->image_->get_buffer_width(), static_cast<int>(std::ceil((x + w) * this->x_scale_)));
+  auto height = std::min(this->image_->get_buffer_height(), static_cast<int>(std::ceil((y + h) * this->y_scale_)));
+  for (int i = x * this->x_scale_; i < width; i++) {
+    for (int j = y * this->y_scale_; j < height; j++) {
+      this->image_->draw_pixel(i, j, color);
+    }
+  }
+}
+
+}  // namespace esphome::runtime_image

esphome/components/runtime_image/image_decoder.h

@@ -1,8 +1,7 @@
 #pragma once
 #include "esphome/core/color.h"
 
-namespace esphome {
-namespace online_image {
+namespace esphome::runtime_image {
 
 enum DecodeError : int {
   DECODE_ERROR_INVALID_TYPE = -1,
@@ -10,7 +9,7 @@ enum DecodeError : int {
   DECODE_ERROR_OUT_OF_MEMORY = -3,
 };
 
-class OnlineImage;
+class RuntimeImage;
 
 /**
  * @brief Class to abstract decoding different image formats.
@@ -20,19 +19,19 @@ class ImageDecoder {
   /**
    * @brief Construct a new Image Decoder object
    *
-   * @param image The image to decode the stream into.
+   * @param image The RuntimeImage to decode the stream into.
    */
-  ImageDecoder(OnlineImage *image) : image_(image) {}
+  ImageDecoder(RuntimeImage *image) : image_(image) {}
   virtual ~ImageDecoder() = default;
 
   /**
    * @brief Initialize the decoder.
    *
-   * @param download_size The total number of bytes that need to be downloaded for the image.
+   * @param expected_size Hint about the expected data size (0 if unknown).
    * @return int          Returns 0 on success, a {@see DecodeError} value in case of an error.
    */
-  virtual int prepare(size_t download_size) {
-    this->download_size_ = download_size;
+  virtual int prepare(size_t expected_size) {
+    this->expected_size_ = expected_size;
     return 0;
   }
 
@@ -73,49 +72,26 @@ class ImageDecoder {
    */
   void draw(int x, int y, int w, int h, const Color &color);
 
-  bool is_finished() const { return this->decoded_bytes_ == this->download_size_; }
+  /**
+   * @brief Check if the decoder has finished processing.
+   *
+   * This should be overridden by decoders that can detect completion
+   * based on format-specific markers rather than byte counts.
+   */
+  virtual bool is_finished() const {
+    if (this->expected_size_ > 0) {
+      return this->decoded_bytes_ >= this->expected_size_;
+    }
+    // If size is unknown, derived classes should override this
+    return false;
+  }
 
  protected:
-  OnlineImage *image_;
-  // Initializing to 1, to ensure it is distinguishable from initial "decoded_bytes_".
-  // Will be overwritten anyway once the download size is known.
-  size_t download_size_ = 1;
-  size_t decoded_bytes_ = 0;
+  RuntimeImage *image_;
+  size_t expected_size_ = 0;  // Expected data size (0 if unknown)
+  size_t decoded_bytes_ = 0;  // Bytes processed so far
   double x_scale_ = 1.0;
   double y_scale_ = 1.0;
 };
 
-class DownloadBuffer {
- public:
-  DownloadBuffer(size_t size);
-
-  virtual ~DownloadBuffer() { this->allocator_.deallocate(this->buffer_, this->size_); }
-
-  uint8_t *data(size_t offset = 0);
-
-  uint8_t *append() { return this->data(this->unread_); }
-
-  size_t unread() const { return this->unread_; }
-  size_t size() const { return this->size_; }
-  size_t free_capacity() const { return this->size_ - this->unread_; }
-
-  size_t read(size_t len);
-  size_t write(size_t len) {
-    this->unread_ += len;
-    return this->unread_;
-  }
-
-  void reset() { this->unread_ = 0; }
-
-  size_t resize(size_t size);
-
- protected:
-  RAMAllocator<uint8_t> allocator_{};
-  uint8_t *buffer_;
-  size_t size_;
-  /** Total number of downloaded bytes not yet read. */
-  size_t unread_;
-};
-
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image

esphome/components/runtime_image/jpeg_decoder.cpp

@@ -1,16 +1,19 @@
-#include "jpeg_image.h"
-#ifdef USE_ONLINE_IMAGE_JPEG_SUPPORT
+#include "jpeg_decoder.h"
+#ifdef USE_RUNTIME_IMAGE_JPEG
 
 #include "esphome/components/display/display_buffer.h"
 #include "esphome/core/application.h"
+#include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-#include "online_image.h"
-static const char *const TAG = "online_image.jpeg";
+#ifdef USE_ESP_IDF
+#include "esp_task_wdt.h"
+#endif
 
-namespace esphome {
-namespace online_image {
+static const char *const TAG = "image_decoder.jpeg";
+
+namespace esphome::runtime_image {
 
 /**
  * @brief Callback method that will be called by the JPEGDEC engine when a chunk
@@ -22,8 +25,14 @@ static int draw_callback(JPEGDRAW *jpeg) {
   ImageDecoder *decoder = (ImageDecoder *) jpeg->pUser;
 
   // Some very big images take too long to decode, so feed the watchdog on each callback
-  // to avoid crashing.
-  App.feed_wdt();
+  // to avoid crashing if the executing task has a watchdog enabled.
+#ifdef USE_ESP_IDF
+  if (esp_task_wdt_status(nullptr) == ESP_OK) {
+#endif
+    App.feed_wdt();
+#ifdef USE_ESP_IDF
+  }
+#endif
   size_t position = 0;
   size_t height = static_cast<size_t>(jpeg->iHeight);
   size_t width = static_cast<size_t>(jpeg->iWidth);
@@ -43,22 +52,23 @@ static int draw_callback(JPEGDRAW *jpeg) {
   return 1;
 }
 
-int JpegDecoder::prepare(size_t download_size) {
-  ImageDecoder::prepare(download_size);
-  auto size = this->image_->resize_download_buffer(download_size);
-  if (size < download_size) {
-    ESP_LOGE(TAG, "Download buffer resize failed!");
-    return DECODE_ERROR_OUT_OF_MEMORY;
-  }
+int JpegDecoder::prepare(size_t expected_size) {
+  ImageDecoder::prepare(expected_size);
+  // JPEG decoder needs complete data before decoding
   return 0;
 }
 
 int HOT JpegDecoder::decode(uint8_t *buffer, size_t size) {
-  if (size < this->download_size_) {
-    ESP_LOGV(TAG, "Download not complete. Size: %d/%d", size, this->download_size_);
+  // JPEG decoder requires complete data
+  // If we know the expected size, wait for it
+  if (this->expected_size_ > 0 && size < this->expected_size_) {
+    ESP_LOGV(TAG, "Download not complete. Size: %zu/%zu", size, this->expected_size_);
     return 0;
   }
 
+  // If size unknown, try to decode and see if it's valid
+  // The JPEGDEC library will fail gracefully if data is incomplete
+
   if (!this->jpeg_.openRAM(buffer, size, draw_callback)) {
     ESP_LOGE(TAG, "Could not open image for decoding: %d", this->jpeg_.getLastError());
     return DECODE_ERROR_INVALID_TYPE;
@@ -88,7 +98,6 @@ int HOT JpegDecoder::decode(uint8_t *buffer, size_t size) {
   return size;
 }
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image
 
-#endif  // USE_ONLINE_IMAGE_JPEG_SUPPORT
+#endif  // USE_RUNTIME_IMAGE_JPEG

esphome/components/runtime_image/jpeg_decoder.h

@@ -1,12 +1,12 @@
 #pragma once
 
 #include "image_decoder.h"
+#include "runtime_image.h"
 #include "esphome/core/defines.h"
-#ifdef USE_ONLINE_IMAGE_JPEG_SUPPORT
+#ifdef USE_RUNTIME_IMAGE_JPEG
 #include <JPEGDEC.h>
 
-namespace esphome {
-namespace online_image {
+namespace esphome::runtime_image {
 
 /**
  * @brief Image decoder specialization for JPEG images.
@@ -16,19 +16,18 @@ class JpegDecoder : public ImageDecoder {
   /**
    * @brief Construct a new JPEG Decoder object.
    *
-   * @param display The image to decode the stream into.
+   * @param image The RuntimeImage to decode the stream into.
    */
-  JpegDecoder(OnlineImage *image) : ImageDecoder(image) {}
+  JpegDecoder(RuntimeImage *image) : ImageDecoder(image) {}
   ~JpegDecoder() override {}
 
-  int prepare(size_t download_size) override;
+  int prepare(size_t expected_size) override;
   int HOT decode(uint8_t *buffer, size_t size) override;
 
  protected:
   JPEGDEC jpeg_{};
 };
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image
 
-#endif  // USE_ONLINE_IMAGE_JPEG_SUPPORT
+#endif  // USE_RUNTIME_IMAGE_JPEG

esphome/components/runtime_image/png_decoder.cpp

@@ -1,15 +1,14 @@
-#include "png_image.h"
-#ifdef USE_ONLINE_IMAGE_PNG_SUPPORT
+#include "png_decoder.h"
+#ifdef USE_RUNTIME_IMAGE_PNG
 
 #include "esphome/components/display/display_buffer.h"
 #include "esphome/core/application.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-static const char *const TAG = "online_image.png";
+static const char *const TAG = "image_decoder.png";
 
-namespace esphome {
-namespace online_image {
+namespace esphome::runtime_image {
 
 /**
  * @brief Callback method that will be called by the PNGLE engine when the basic
@@ -49,7 +48,7 @@ static void draw_callback(pngle_t *pngle, uint32_t x, uint32_t y, uint32_t w, ui
   }
 }
 
-PngDecoder::PngDecoder(OnlineImage *image) : ImageDecoder(image) {
+PngDecoder::PngDecoder(RuntimeImage *image) : ImageDecoder(image) {
   {
     pngle_t *pngle = this->allocator_.allocate(1, PNGLE_T_SIZE);
     if (!pngle) {
@@ -69,8 +68,8 @@ PngDecoder::~PngDecoder() {
   }
 }
 
-int PngDecoder::prepare(size_t download_size) {
-  ImageDecoder::prepare(download_size);
+int PngDecoder::prepare(size_t expected_size) {
+  ImageDecoder::prepare(expected_size);
   if (!this->pngle_) {
     ESP_LOGE(TAG, "PNG decoder engine not initialized!");
     return DECODE_ERROR_OUT_OF_MEMORY;
@@ -86,8 +85,9 @@ int HOT PngDecoder::decode(uint8_t *buffer, size_t size) {
     ESP_LOGE(TAG, "PNG decoder engine not initialized!");
     return DECODE_ERROR_OUT_OF_MEMORY;
   }
-  if (size < 256 && size < this->download_size_ - this->decoded_bytes_) {
-    ESP_LOGD(TAG, "Waiting for data");
+  // PNG can be decoded progressively, but wait for a reasonable chunk
+  if (size < 256 && this->expected_size_ > 0 && size < this->expected_size_ - this->decoded_bytes_) {
+    ESP_LOGD(TAG, "Waiting for more data");
     return 0;
   }
   auto fed = pngle_feed(this->pngle_, buffer, size);
@@ -99,7 +99,6 @@ int HOT PngDecoder::decode(uint8_t *buffer, size_t size) {
   return fed;
 }
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image
 
-#endif  // USE_ONLINE_IMAGE_PNG_SUPPORT
+#endif  // USE_RUNTIME_IMAGE_PNG

esphome/components/runtime_image/png_decoder.h

@@ -3,11 +3,11 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 #include "image_decoder.h"
-#ifdef USE_ONLINE_IMAGE_PNG_SUPPORT
+#include "runtime_image.h"
+#ifdef USE_RUNTIME_IMAGE_PNG
 #include <pngle.h>
 
-namespace esphome {
-namespace online_image {
+namespace esphome::runtime_image {
 
 /**
  * @brief Image decoder specialization for PNG images.
@@ -17,12 +17,12 @@ class PngDecoder : public ImageDecoder {
   /**
    * @brief Construct a new PNG Decoder object.
    *
-   * @param display The image to decode the stream into.
+   * @param image The RuntimeImage to decode the stream into.
    */
-  PngDecoder(OnlineImage *image);
+  PngDecoder(RuntimeImage *image);
   ~PngDecoder() override;
 
-  int prepare(size_t download_size) override;
+  int prepare(size_t expected_size) override;
   int HOT decode(uint8_t *buffer, size_t size) override;
 
   void increment_pixels_decoded(uint32_t count) { this->pixels_decoded_ += count; }
@@ -30,11 +30,10 @@ class PngDecoder : public ImageDecoder {
 
  protected:
   RAMAllocator<pngle_t> allocator_;
-  pngle_t *pngle_;
+  pngle_t *pngle_{nullptr};
   uint32_t pixels_decoded_{0};
 };
 
-}  // namespace online_image
-}  // namespace esphome
+}  // namespace esphome::runtime_image
 
-#endif  // USE_ONLINE_IMAGE_PNG_SUPPORT
+#endif  // USE_RUNTIME_IMAGE_PNG

esphome/components/runtime_image/runtime_image.cpp

@@ -0,0 +1,300 @@
+#include "runtime_image.h"
+#include "image_decoder.h"
+#include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
+#include <cstring>
+
+#ifdef USE_RUNTIME_IMAGE_BMP
+#include "bmp_decoder.h"
+#endif
+#ifdef USE_RUNTIME_IMAGE_JPEG
+#include "jpeg_decoder.h"
+#endif
+#ifdef USE_RUNTIME_IMAGE_PNG
+#include "png_decoder.h"
+#endif
+
+namespace esphome::runtime_image {
+
+static const char *const TAG = "runtime_image";
+
+inline bool is_color_on(const Color &color) {
+  // This produces the most accurate monochrome conversion, but is slightly slower.
+  //  return (0.2125 * color.r + 0.7154 * color.g + 0.0721 * color.b) > 127;
+
+  // Approximation using fast integer computations; produces acceptable results
+  // Equivalent to 0.25 * R + 0.5 * G + 0.25 * B
+  return ((color.r >> 2) + (color.g >> 1) + (color.b >> 2)) & 0x80;
+}
+
+RuntimeImage::RuntimeImage(ImageFormat format, image::ImageType type, image::Transparency transparency,
+                           image::Image *placeholder, bool is_big_endian, int fixed_width, int fixed_height)
+    : Image(nullptr, 0, 0, type, transparency),
+      format_(format),
+      fixed_width_(fixed_width),
+      fixed_height_(fixed_height),
+      placeholder_(placeholder),
+      is_big_endian_(is_big_endian) {}
+
+RuntimeImage::~RuntimeImage() { this->release(); }
+
+int RuntimeImage::resize(int width, int height) {
+  // Use fixed dimensions if specified (0 means auto-resize)
+  int target_width = this->fixed_width_ ? this->fixed_width_ : width;
+  int target_height = this->fixed_height_ ? this->fixed_height_ : height;
+
+  size_t result = this->resize_buffer_(target_width, target_height);
+  if (result > 0 && this->progressive_display_) {
+    // Update display dimensions for progressive display
+    this->width_ = this->buffer_width_;
+    this->height_ = this->buffer_height_;
+    this->data_start_ = this->buffer_;
+  }
+  return result;
+}
+
+void RuntimeImage::draw_pixel(int x, int y, const Color &color) {
+  if (!this->buffer_) {
+    ESP_LOGE(TAG, "Buffer not allocated!");
+    return;
+  }
+  if (x < 0 || y < 0 || x >= this->buffer_width_ || y >= this->buffer_height_) {
+    ESP_LOGE(TAG, "Tried to paint a pixel (%d,%d) outside the image!", x, y);
+    return;
+  }
+
+  switch (this->type_) {
+    case image::IMAGE_TYPE_BINARY: {
+      const uint32_t width_8 = ((this->buffer_width_ + 7u) / 8u) * 8u;
+      uint32_t pos = x + y * width_8;
+      auto bitno = 0x80 >> (pos % 8u);
+      pos /= 8u;
+      auto on = is_color_on(color);
+      if (this->has_transparency() && color.w < 0x80)
+        on = false;
+      if (on) {
+        this->buffer_[pos] |= bitno;
+      } else {
+        this->buffer_[pos] &= ~bitno;
+      }
+      break;
+    }
+    case image::IMAGE_TYPE_GRAYSCALE: {
+      uint32_t pos = this->get_position_(x, y);
+      auto gray = static_cast<uint8_t>(0.2125 * color.r + 0.7154 * color.g + 0.0721 * color.b);
+      if (this->transparency_ == image::TRANSPARENCY_CHROMA_KEY) {
+        if (gray == 1) {
+          gray = 0;
+        }
+        if (color.w < 0x80) {
+          gray = 1;
+        }
+      } else if (this->transparency_ == image::TRANSPARENCY_ALPHA_CHANNEL) {
+        if (color.w != 0xFF)
+          gray = color.w;
+      }
+      this->buffer_[pos] = gray;
+      break;
+    }
+    case image::IMAGE_TYPE_RGB565: {
+      uint32_t pos = this->get_position_(x, y);
+      Color mapped_color = color;
+      this->map_chroma_key(mapped_color);
+      uint16_t rgb565 = display::ColorUtil::color_to_565(mapped_color);
+      if (this->is_big_endian_) {
+        this->buffer_[pos + 0] = static_cast<uint8_t>((rgb565 >> 8) & 0xFF);
+        this->buffer_[pos + 1] = static_cast<uint8_t>(rgb565 & 0xFF);
+      } else {
+        this->buffer_[pos + 0] = static_cast<uint8_t>(rgb565 & 0xFF);
+        this->buffer_[pos + 1] = static_cast<uint8_t>((rgb565 >> 8) & 0xFF);
+      }
+      if (this->transparency_ == image::TRANSPARENCY_ALPHA_CHANNEL) {
+        this->buffer_[pos + 2] = color.w;
+      }
+      break;
+    }
+    case image::IMAGE_TYPE_RGB: {
+      uint32_t pos = this->get_position_(x, y);
+      Color mapped_color = color;
+      this->map_chroma_key(mapped_color);
+      this->buffer_[pos + 0] = mapped_color.r;
+      this->buffer_[pos + 1] = mapped_color.g;
+      this->buffer_[pos + 2] = mapped_color.b;
+      if (this->transparency_ == image::TRANSPARENCY_ALPHA_CHANNEL) {
+        this->buffer_[pos + 3] = color.w;
+      }
+      break;
+    }
+  }
+}
+
+void RuntimeImage::map_chroma_key(Color &color) {
+  if (this->transparency_ == image::TRANSPARENCY_CHROMA_KEY) {
+    if (color.g == 1 && color.r == 0 && color.b == 0) {
+      color.g = 0;
+    }
+    if (color.w < 0x80) {
+      color.r = 0;
+      color.g = this->type_ == image::IMAGE_TYPE_RGB565 ? 4 : 1;
+      color.b = 0;
+    }
+  }
+}
+
+void RuntimeImage::draw(int x, int y, display::Display *display, Color color_on, Color color_off) {
+  if (this->data_start_) {
+    // If we have a complete image, use the base class draw method
+    Image::draw(x, y, display, color_on, color_off);
+  } else if (this->placeholder_) {
+    // Show placeholder while the runtime image is not available
+    this->placeholder_->draw(x, y, display, color_on, color_off);
+  }
+  // If no image is loaded and no placeholder, nothing to draw
+}
+
+bool RuntimeImage::begin_decode(size_t expected_size) {
+  if (this->decoder_) {
+    ESP_LOGW(TAG, "Decoding already in progress");
+    return false;
+  }
+
+  this->decoder_ = this->create_decoder_();
+  if (!this->decoder_) {
+    ESP_LOGE(TAG, "Failed to create decoder for format %d", this->format_);
+    return false;
+  }
+
+  this->total_size_ = expected_size;
+  this->decoded_bytes_ = 0;
+
+  // Initialize decoder
+  int result = this->decoder_->prepare(expected_size);
+  if (result < 0) {
+    ESP_LOGE(TAG, "Failed to prepare decoder: %d", result);
+    this->decoder_ = nullptr;
+    return false;
+  }
+
+  return true;
+}
+
+int RuntimeImage::feed_data(uint8_t *data, size_t len) {
+  if (!this->decoder_) {
+    ESP_LOGE(TAG, "No decoder initialized");
+    return -1;
+  }
+
+  int consumed = this->decoder_->decode(data, len);
+  if (consumed > 0) {
+    this->decoded_bytes_ += consumed;
+  }
+
+  return consumed;
+}
+
+bool RuntimeImage::end_decode() {
+  if (!this->decoder_) {
+    return false;
+  }
+
+  // Finalize the image for display
+  if (!this->progressive_display_) {
+    // Only now make the image visible
+    this->width_ = this->buffer_width_;
+    this->height_ = this->buffer_height_;
+    this->data_start_ = this->buffer_;
+  }
+
+  // Clean up decoder
+  this->decoder_ = nullptr;
+
+  ESP_LOGD(TAG, "Decoding complete: %dx%d, %zu bytes", this->width_, this->height_, this->decoded_bytes_);
+  return true;
+}
+
+bool RuntimeImage::is_decode_finished() const {
+  if (!this->decoder_) {
+    return false;
+  }
+  return this->decoder_->is_finished();
+}
+
+void RuntimeImage::release() {
+  this->release_buffer_();
+  // Reset decoder separately — release() can be called from within the decoder
+  // (via set_size -> resize -> resize_buffer_), so we must not destroy the decoder here.
+  // The decoder lifecycle is managed by begin_decode()/end_decode().
+  this->decoder_ = nullptr;
+}
+
+void RuntimeImage::release_buffer_() {
+  if (this->buffer_) {
+    ESP_LOGV(TAG, "Releasing buffer of size %zu", this->get_buffer_size_(this->buffer_width_, this->buffer_height_));
+    this->allocator_.deallocate(this->buffer_, this->get_buffer_size_(this->buffer_width_, this->buffer_height_));
+    this->buffer_ = nullptr;
+    this->data_start_ = nullptr;
+    this->width_ = 0;
+    this->height_ = 0;
+    this->buffer_width_ = 0;
+    this->buffer_height_ = 0;
+  }
+}
+
+size_t RuntimeImage::resize_buffer_(int width, int height) {
+  size_t new_size = this->get_buffer_size_(width, height);
+
+  if (this->buffer_ && this->buffer_width_ == width && this->buffer_height_ == height) {
+    // Buffer already allocated with correct size
+    return new_size;
+  }
+
+  // Release old buffer if dimensions changed
+  if (this->buffer_) {
+    this->release_buffer_();
+  }
+
+  ESP_LOGD(TAG, "Allocating buffer: %dx%d, %zu bytes", width, height, new_size);
+  this->buffer_ = this->allocator_.allocate(new_size);
+
+  if (!this->buffer_) {
+    ESP_LOGE(TAG, "Failed to allocate %zu bytes. Largest free block: %zu", new_size,
+             this->allocator_.get_max_free_block_size());
+    return 0;
+  }
+
+  // Clear buffer
+  memset(this->buffer_, 0, new_size);
+
+  this->buffer_width_ = width;
+  this->buffer_height_ = height;
+
+  return new_size;
+}
+
+size_t RuntimeImage::get_buffer_size_(int width, int height) const {
+  return (this->get_bpp() * width + 7u) / 8u * height;
+}
+
+int RuntimeImage::get_position_(int x, int y) const { return (x + y * this->buffer_width_) * this->get_bpp() / 8; }
+
+std::unique_ptr<ImageDecoder> RuntimeImage::create_decoder_() {
+  switch (this->format_) {
+#ifdef USE_RUNTIME_IMAGE_BMP
+    case BMP:
+      return make_unique<BmpDecoder>(this);
+#endif
+#ifdef USE_RUNTIME_IMAGE_JPEG
+    case JPEG:
+      return make_unique<JpegDecoder>(this);
+#endif
+#ifdef USE_RUNTIME_IMAGE_PNG
+    case PNG:
+      return make_unique<PngDecoder>(this);
+#endif
+    default:
+      ESP_LOGE(TAG, "Unsupported image format: %d", this->format_);
+      return nullptr;
+  }
+}
+
+}  // namespace esphome::runtime_image

esphome/components/runtime_image/runtime_image.h

@@ -0,0 +1,214 @@
+#pragma once
+
+#include "esphome/components/image/image.h"
+#include "esphome/core/helpers.h"
+
+namespace esphome::runtime_image {
+
+// Forward declaration
+class ImageDecoder;
+
+/**
+ * @brief Image format types that can be decoded dynamically.
+ */
+enum ImageFormat {
+  /** Automatically detect from data. Not implemented yet. */
+  AUTO,
+  /** JPEG format. */
+  JPEG,
+  /** PNG format. */
+  PNG,
+  /** BMP format. */
+  BMP,
+};
+
+/**
+ * @brief A dynamic image that can be loaded and decoded at runtime.
+ *
+ * This class provides dynamic buffer allocation and management for images
+ * that are decoded at runtime, as opposed to static images compiled into
+ * the firmware. It serves as a base class for components that need to
+ * load images dynamically from various sources.
+ */
+class RuntimeImage : public image::Image {
+ public:
+  /**
+   * @brief Construct a new RuntimeImage object.
+   *
+   * @param format The image format to decode.
+   * @param type The pixel format for the image.
+   * @param transparency The transparency type for the image.
+   * @param placeholder Optional placeholder image to show while loading.
+   * @param is_big_endian Whether the image is stored in big-endian format.
+   * @param fixed_width Fixed width for the image (0 for auto-resize).
+   * @param fixed_height Fixed height for the image (0 for auto-resize).
+   */
+  RuntimeImage(ImageFormat format, image::ImageType type, image::Transparency transparency,
+               image::Image *placeholder = nullptr, bool is_big_endian = false, int fixed_width = 0,
+               int fixed_height = 0);
+
+  ~RuntimeImage();
+
+  // Decoder interface methods
+  /**
+   * @brief Resize the image buffer to the requested dimensions.
+   *
+   * The buffer will be allocated if not existing.
+   * If fixed dimensions have been specified in the constructor, the buffer will be created
+   * with those dimensions and not resized, even on request.
+   * Otherwise, the old buffer will be deallocated and a new buffer with the requested
+   * dimensions allocated.
+   *
+   * @param width Requested width (ignored if fixed_width_ is set)
+   * @param height Requested height (ignored if fixed_height_ is set)
+   * @return Size of the allocated buffer in bytes, or 0 if allocation failed.
+   */
+  int resize(int width, int height);
+  void draw_pixel(int x, int y, const Color &color);
+  void map_chroma_key(Color &color);
+  int get_buffer_width() const { return this->buffer_width_; }
+  int get_buffer_height() const { return this->buffer_height_; }
+
+  // Image drawing interface
+  void draw(int x, int y, display::Display *display, Color color_on, Color color_off) override;
+
+  /**
+   * @brief Begin decoding an image.
+   *
+   * @param expected_size Optional hint about the expected data size.
+   * @return true if decoder was successfully initialized.
+   */
+  bool begin_decode(size_t expected_size = 0);
+
+  /**
+   * @brief Feed data to the decoder.
+   *
+   * @param data Pointer to the data buffer.
+   * @param len Length of data to process.
+   * @return Number of bytes consumed by the decoder.
+   */
+  int feed_data(uint8_t *data, size_t len);
+
+  /**
+   * @brief Complete the decoding process.
+   *
+   * @return true if decoding completed successfully.
+   */
+  bool end_decode();
+
+  /**
+   * @brief Check if decoding is currently in progress.
+   */
+  bool is_decoding() const { return this->decoder_ != nullptr; }
+
+  /**
+   * @brief Check if the decoder has finished processing all data.
+   *
+   * This delegates to the decoder's format-specific completion check,
+   * which handles both known-size and chunked transfer cases.
+   */
+  bool is_decode_finished() const;
+
+  /**
+   * @brief Check if an image is currently loaded.
+   */
+  bool is_loaded() const { return this->buffer_ != nullptr; }
+
+  /**
+   * @brief Get the image format.
+   */
+  ImageFormat get_format() const { return this->format_; }
+
+  /**
+   * @brief Release the image buffer and free memory.
+   */
+  void release();
+
+  /**
+   * @brief Set whether to allow progressive display during decode.
+   *
+   * When enabled, the image can be displayed even while still decoding.
+   * When disabled, the image is only displayed after decoding completes.
+   */
+  void set_progressive_display(bool progressive) { this->progressive_display_ = progressive; }
+
+ protected:
+  /**
+   * @brief Resize the image buffer to the requested dimensions.
+   *
+   * @param width New width in pixels.
+   * @param height New height in pixels.
+   * @return Size of the allocated buffer, or 0 on failure.
+   */
+  size_t resize_buffer_(int width, int height);
+
+  /**
+   * @brief Release only the image buffer without resetting the decoder.
+   *
+   * This is safe to call from within the decoder (e.g., during resize).
+   */
+  void release_buffer_();
+
+  /**
+   * @brief Get the buffer size in bytes for given dimensions.
+   */
+  size_t get_buffer_size_(int width, int height) const;
+
+  /**
+   * @brief Get the position in the buffer for a pixel.
+   */
+  int get_position_(int x, int y) const;
+
+  /**
+   * @brief Create decoder instance for the image's format.
+   */
+  std::unique_ptr<ImageDecoder> create_decoder_();
+
+  // Memory management
+  RAMAllocator<uint8_t> allocator_{};
+  uint8_t *buffer_{nullptr};
+
+  // Decoder management
+  std::unique_ptr<ImageDecoder> decoder_{nullptr};
+  /** The image format this RuntimeImage is configured to decode. */
+  const ImageFormat format_;
+
+  /**
+   * Actual width of the current image.
+   * This needs to be separate from "Image::get_width()" because the latter
+   * must return 0 until the image has been decoded (to avoid showing partially
+   * decoded images). When progressive_display_ is enabled, Image dimensions
+   * are updated during decoding to allow rendering in progress.
+   */
+  int buffer_width_{0};
+  /**
+   * Actual height of the current image.
+   * This needs to be separate from "Image::get_height()" because the latter
+   * must return 0 until the image has been decoded (to avoid showing partially
+   * decoded images). When progressive_display_ is enabled, Image dimensions
+   * are updated during decoding to allow rendering in progress.
+   */
+  int buffer_height_{0};
+
+  // Decoding state
+  size_t total_size_{0};
+  size_t decoded_bytes_{0};
+
+  /** Fixed width requested on configuration, or 0 if not specified. */
+  const int fixed_width_{0};
+  /** Fixed height requested on configuration, or 0 if not specified. */
+  const int fixed_height_{0};
+
+  /** Placeholder image to show when the runtime image is not available. */
+  image::Image *placeholder_{nullptr};
+
+  // Configuration
+  bool progressive_display_{false};
+  /**
+   * Whether the image is stored in big-endian format.
+   * This is used to determine how to store 16 bit colors in the buffer.
+   */
+  bool is_big_endian_{false};
+};
+
+}  // namespace esphome::runtime_image

esphome/components/serial_proxy/__init__.py

@@ -0,0 +1,80 @@
+"""
+Serial Proxy component for ESPHome.
+
+WARNING: This component is EXPERIMENTAL. The API (both Python configuration
+and C++ interfaces) may change at any time without following the normal
+breaking changes policy. Use at your own risk.
+
+Once the API is considered stable, this warning will be removed.
+
+Provides a proxy to/from a serial interface on the ESPHome device, allowing
+Home Assistant to connect to the serial port and send/receive data to/from
+an arbitrary serial device.
+"""
+
+from esphome import pins
+import esphome.codegen as cg
+from esphome.components import uart
+import esphome.config_validation as cv
+from esphome.const import CONF_ID, CONF_NAME
+
+CODEOWNERS = ["@kbx81"]
+DEPENDENCIES = ["api", "uart"]
+
+MULTI_CONF = True
+
+serial_proxy_ns = cg.esphome_ns.namespace("serial_proxy")
+SerialProxy = serial_proxy_ns.class_("SerialProxy", cg.Component, uart.UARTDevice)
+
+api_enums_ns = cg.esphome_ns.namespace("api").namespace("enums")
+SerialProxyPortType = api_enums_ns.enum("SerialProxyPortType")
+SERIAL_PROXY_PORT_TYPES = {
+    "TTL": SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_TTL,
+    "RS232": SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_RS232,
+    "RS485": SerialProxyPortType.SERIAL_PROXY_PORT_TYPE_RS485,
+}
+
+CONF_DTR_PIN = "dtr_pin"
+CONF_PORT_TYPE = "port_type"
+CONF_RTS_PIN = "rts_pin"
+
+_serial_proxy_count = []
+
+
+CONFIG_SCHEMA = (
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(SerialProxy),
+            cv.Required(CONF_NAME): cv.string_strict,
+            cv.Required(CONF_PORT_TYPE): cv.enum(SERIAL_PROXY_PORT_TYPES, upper=True),
+            cv.Optional(CONF_RTS_PIN): pins.gpio_output_pin_schema,
+            cv.Optional(CONF_DTR_PIN): pins.gpio_output_pin_schema,
+        }
+    )
+    .extend(cv.COMPONENT_SCHEMA)
+    .extend(uart.UART_DEVICE_SCHEMA)
+)
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await cg.register_component(var, config)
+    await uart.register_uart_device(var, config)
+    cg.add(cg.App.register_serial_proxy(var))
+    cg.add(var.set_name(config[CONF_NAME]))
+    cg.add(var.set_port_type(config[CONF_PORT_TYPE]))
+    cg.add_define("USE_SERIAL_PROXY")
+    # Track instance count — last define wins, so the final value is the total count
+    _serial_proxy_count.append(var)
+    cg.add_define("SERIAL_PROXY_COUNT", len(_serial_proxy_count))
+
+    if CONF_RTS_PIN in config:
+        rts_pin = await cg.gpio_pin_expression(config[CONF_RTS_PIN])
+        cg.add(var.set_rts_pin(rts_pin))
+
+    if CONF_DTR_PIN in config:
+        dtr_pin = await cg.gpio_pin_expression(config[CONF_DTR_PIN])
+        cg.add(var.set_dtr_pin(dtr_pin))
+
+    # Request UART to wake the main loop when data arrives for low-latency processing
+    uart.request_wake_loop_on_rx()

esphome/components/serial_proxy/serial_proxy.cpp

@@ -0,0 +1,137 @@
+#include "serial_proxy.h"
+
+#ifdef USE_SERIAL_PROXY
+
+#include "esphome/core/log.h"
+
+#ifdef USE_API
+#include "esphome/components/api/api_server.h"
+#endif
+
+namespace esphome::serial_proxy {
+
+static const char *const TAG = "serial_proxy";
+
+void SerialProxy::setup() {
+  // Set up modem control pins if configured
+  if (this->rts_pin_ != nullptr) {
+    this->rts_pin_->setup();
+    this->rts_pin_->digital_write(this->rts_state_);
+  }
+  if (this->dtr_pin_ != nullptr) {
+    this->dtr_pin_->setup();
+    this->dtr_pin_->digital_write(this->dtr_state_);
+  }
+}
+
+void SerialProxy::loop() {
+  // Read available data from UART and forward to API clients
+  size_t available = this->available();
+  if (available == 0)
+    return;
+
+  // Read in chunks up to SERIAL_PROXY_MAX_READ_SIZE
+  uint8_t buffer[SERIAL_PROXY_MAX_READ_SIZE];
+  size_t to_read = std::min(available, sizeof(buffer));
+
+  if (!this->read_array(buffer, to_read))
+    return;
+
+#ifdef USE_API
+  if (api::global_api_server != nullptr) {
+    api::global_api_server->send_serial_proxy_data(this->instance_index_, buffer, to_read);
+  }
+#endif
+}
+
+void SerialProxy::dump_config() {
+  ESP_LOGCONFIG(TAG,
+                "Serial Proxy [%u]:\n"
+                "  Name: %s\n"
+                "  Port Type: %s\n"
+                "  RTS Pin: %s\n"
+                "  DTR Pin: %s",
+                this->instance_index_, this->name_.c_str(),
+                this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_RS485   ? "RS485"
+                : this->port_type_ == api::enums::SERIAL_PROXY_PORT_TYPE_RS232 ? "RS232"
+                                                                               : "TTL",
+                this->rts_pin_ != nullptr ? "configured" : "not configured",
+                this->dtr_pin_ != nullptr ? "configured" : "not configured");
+}
+
+void SerialProxy::configure(uint32_t baudrate, bool flow_control, uint8_t parity, uint8_t stop_bits,
+                            uint8_t data_size) {
+  ESP_LOGD(TAG, "Configuring serial proxy [%u]: baud=%u, flow_ctrl=%s, parity=%u, stop=%u, data=%u",
+           this->instance_index_, baudrate, YESNO(flow_control), parity, stop_bits, data_size);
+
+  auto *uart_comp = this->parent_;
+  if (uart_comp == nullptr) {
+    ESP_LOGE(TAG, "UART component not available");
+    return;
+  }
+
+  // Apply UART parameters
+  uart_comp->set_baud_rate(baudrate);
+  uart_comp->set_stop_bits(stop_bits);
+  uart_comp->set_data_bits(data_size);
+
+  // Map parity enum to UARTParityOptions
+  switch (parity) {
+    case 0:
+      uart_comp->set_parity(uart::UART_CONFIG_PARITY_NONE);
+      break;
+    case 1:
+      uart_comp->set_parity(uart::UART_CONFIG_PARITY_EVEN);
+      break;
+    case 2:
+      uart_comp->set_parity(uart::UART_CONFIG_PARITY_ODD);
+      break;
+    default:
+      ESP_LOGW(TAG, "Unknown parity value: %u, using NONE", parity);
+      uart_comp->set_parity(uart::UART_CONFIG_PARITY_NONE);
+      break;
+  }
+
+    // Apply the new settings
+    // load_settings() is available on ESP8266 and ESP32 platforms
+#if defined(USE_ESP8266) || defined(USE_ESP32)
+  uart_comp->load_settings(true);
+#endif
+
+  // Note: Hardware flow control configuration is stored but not yet applied
+  // to the UART hardware - this requires additional platform support
+  (void) flow_control;
+}
+
+void SerialProxy::write(const uint8_t *data, size_t len) {
+  if (data == nullptr || len == 0)
+    return;
+  this->write_array(data, len);
+}
+
+void SerialProxy::set_modem_pins(bool rts, bool dtr) {
+  ESP_LOGV(TAG, "Setting modem pins [%u]: RTS=%s, DTR=%s", this->instance_index_, ONOFF(rts), ONOFF(dtr));
+
+  if (this->rts_pin_ != nullptr) {
+    this->rts_state_ = rts;
+    this->rts_pin_->digital_write(rts);
+  }
+  if (this->dtr_pin_ != nullptr) {
+    this->dtr_state_ = dtr;
+    this->dtr_pin_->digital_write(dtr);
+  }
+}
+
+void SerialProxy::get_modem_pins(bool &rts, bool &dtr) const {
+  rts = this->rts_state_;
+  dtr = this->dtr_state_;
+}
+
+void SerialProxy::flush_port() {
+  ESP_LOGV(TAG, "Flushing serial proxy [%u]", this->instance_index_);
+  this->flush();
+}
+
+}  // namespace esphome::serial_proxy
+
+#endif  // USE_SERIAL_PROXY

esphome/components/serial_proxy/serial_proxy.h

@@ -0,0 +1,101 @@
+#pragma once
+
+// WARNING: This component is EXPERIMENTAL. The API may change at any time
+// without following the normal breaking changes policy. Use at your own risk.
+// Once the API is considered stable, this warning will be removed.
+
+#include "esphome/core/defines.h"
+
+#ifdef USE_SERIAL_PROXY
+
+#include "esphome/components/api/api_pb2.h"
+#include "esphome/core/component.h"
+#include "esphome/core/hal.h"
+#include "esphome/components/uart/uart.h"
+
+#include <string>
+
+namespace esphome::serial_proxy {
+
+/// Maximum bytes to read from UART in a single loop iteration
+static constexpr size_t SERIAL_PROXY_MAX_READ_SIZE = 256;
+
+class SerialProxy : public uart::UARTDevice, public Component {
+ public:
+  void setup() override;
+  void loop() override;
+  void dump_config() override;
+  float get_setup_priority() const override { return setup_priority::AFTER_CONNECTION; }
+
+  /// Get the instance index (position in Application's serial_proxies_ vector)
+  uint32_t get_instance_index() const { return this->instance_index_; }
+
+  /// Set the instance index (called by Application::register_serial_proxy)
+  void set_instance_index(uint32_t index) { this->instance_index_ = index; }
+
+  /// Set the human-readable port name (from YAML configuration)
+  void set_name(const std::string &name) { this->name_ = name; }
+
+  /// Get the human-readable port name
+  const std::string &get_name() const { return this->name_; }
+
+  /// Set the port type (from YAML configuration)
+  void set_port_type(api::enums::SerialProxyPortType port_type) { this->port_type_ = port_type; }
+
+  /// Get the port type
+  api::enums::SerialProxyPortType get_port_type() const { return this->port_type_; }
+
+  /// Configure UART parameters and apply them
+  /// @param baudrate Baud rate in bits per second
+  /// @param flow_control True to enable hardware flow control
+  /// @param parity Parity setting (0=none, 1=even, 2=odd)
+  /// @param stop_bits Number of stop bits (1 or 2)
+  /// @param data_size Number of data bits (5-8)
+  void configure(uint32_t baudrate, bool flow_control, uint8_t parity, uint8_t stop_bits, uint8_t data_size);
+
+  /// Write data to the serial device
+  /// @param data Pointer to data buffer
+  /// @param len Number of bytes to write
+  void write(const uint8_t *data, size_t len);
+
+  /// Set modem pin states (RTS and DTR)
+  /// @param rts Desired RTS pin state
+  /// @param dtr Desired DTR pin state
+  void set_modem_pins(bool rts, bool dtr);
+
+  /// Get current modem pin states
+  /// @param[out] rts Current RTS pin state
+  /// @param[out] dtr Current DTR pin state
+  void get_modem_pins(bool &rts, bool &dtr) const;
+
+  /// Flush the serial port (block until all TX data is sent)
+  void flush_port();
+
+  /// Set the RTS GPIO pin (from YAML configuration)
+  void set_rts_pin(GPIOPin *pin) { this->rts_pin_ = pin; }
+
+  /// Set the DTR GPIO pin (from YAML configuration)
+  void set_dtr_pin(GPIOPin *pin) { this->dtr_pin_ = pin; }
+
+ protected:
+  /// Instance index for identifying this proxy in API messages
+  uint32_t instance_index_{0};
+
+  /// Human-readable port name
+  std::string name_;
+
+  /// Port type
+  api::enums::SerialProxyPortType port_type_{api::enums::SERIAL_PROXY_PORT_TYPE_TTL};
+
+  /// Optional GPIO pins for modem control
+  GPIOPin *rts_pin_{nullptr};
+  GPIOPin *dtr_pin_{nullptr};
+
+  /// Current modem pin states
+  bool rts_state_{false};
+  bool dtr_state_{false};
+};
+
+}  // namespace esphome::serial_proxy
+
+#endif  // USE_SERIAL_PROXY

esphome/components/uart/uart_component_esp_idf.cpp

@@ -90,7 +90,6 @@ void IDFUARTComponent::setup() {
     return;
   }
   this->uart_num_ = static_cast<uart_port_t>(next_uart_num++);
-  this->lock_ = xSemaphoreCreateMutex();
 
 #if (SOC_UART_LP_NUM >= 1)
   size_t fifo_len = ((this->uart_num_ < SOC_UART_HP_NUM) ? SOC_UART_FIFO_LEN : SOC_LP_UART_FIFO_LEN);
@@ -102,11 +101,7 @@ void IDFUARTComponent::setup() {
     this->rx_buffer_size_ = fifo_len * 2;
   }
 
-  xSemaphoreTake(this->lock_, portMAX_DELAY);
-
   this->load_settings(false);
-
-  xSemaphoreGive(this->lock_);
 }
 
 void IDFUARTComponent::load_settings(bool dump_config) {
@@ -126,13 +121,20 @@ void IDFUARTComponent::load_settings(bool dump_config) {
       return;
     }
   }
+#ifdef USE_UART_WAKE_LOOP_ON_RX
+  constexpr int event_queue_size = 20;
+  QueueHandle_t *event_queue_ptr = &this->uart_event_queue_;
+#else
+  constexpr int event_queue_size = 0;
+  QueueHandle_t *event_queue_ptr = nullptr;
+#endif
   err = uart_driver_install(this->uart_num_,        // UART number
                             this->rx_buffer_size_,  // RX ring buffer size
-                            0,   // TX ring buffer size. If zero, driver will not use a TX buffer and TX function will
-                                 // block task until all data has been sent out
-                            20,  // event queue size/depth
-                            &this->uart_event_queue_,  // event queue
-                            0                          // Flags used to allocate the interrupt
+                            0,  // TX ring buffer size. If zero, driver will not use a TX buffer and TX function will
+                                // block task until all data has been sent out
+                            event_queue_size,  // event queue size/depth
+                            event_queue_ptr,   // event queue
+                            0                  // Flags used to allocate the interrupt
   );
   if (err != ESP_OK) {
     ESP_LOGW(TAG, "uart_driver_install failed: %s", esp_err_to_name(err));
@@ -282,9 +284,7 @@ void IDFUARTComponent::set_rx_timeout(size_t rx_timeout) {
 }
 
 void IDFUARTComponent::write_array(const uint8_t *data, size_t len) {
-  xSemaphoreTake(this->lock_, portMAX_DELAY);
   int32_t write_len = uart_write_bytes(this->uart_num_, data, len);
-  xSemaphoreGive(this->lock_);
   if (write_len != (int32_t) len) {
     ESP_LOGW(TAG, "uart_write_bytes failed: %d != %zu", write_len, len);
     this->mark_failed();
@@ -299,7 +299,6 @@ void IDFUARTComponent::write_array(const uint8_t *data, size_t len) {
 bool IDFUARTComponent::peek_byte(uint8_t *data) {
   if (!this->check_read_timeout_())
     return false;
-  xSemaphoreTake(this->lock_, portMAX_DELAY);
   if (this->has_peek_) {
     *data = this->peek_byte_;
   } else {
@@ -311,7 +310,6 @@ bool IDFUARTComponent::peek_byte(uint8_t *data) {
       this->peek_byte_ = *data;
     }
   }
-  xSemaphoreGive(this->lock_);
   return true;
 }
 
@@ -320,7 +318,6 @@ bool IDFUARTComponent::read_array(uint8_t *data, size_t len) {
   int32_t read_len = 0;
   if (!this->check_read_timeout_(len))
     return false;
-  xSemaphoreTake(this->lock_, portMAX_DELAY);
   if (this->has_peek_) {
     length_to_read--;
     *data = this->peek_byte_;
@@ -329,7 +326,6 @@ bool IDFUARTComponent::read_array(uint8_t *data, size_t len) {
   }
   if (length_to_read > 0)
     read_len = uart_read_bytes(this->uart_num_, data, length_to_read, 20 / portTICK_PERIOD_MS);
-  xSemaphoreGive(this->lock_);
 #ifdef USE_UART_DEBUGGER
   for (size_t i = 0; i < len; i++) {
     this->debug_callback_.call(UART_DIRECTION_RX, data[i]);
@@ -342,9 +338,7 @@ size_t IDFUARTComponent::available() {
   size_t available = 0;
   esp_err_t err;
 
-  xSemaphoreTake(this->lock_, portMAX_DELAY);
   err = uart_get_buffered_data_len(this->uart_num_, &available);
-  xSemaphoreGive(this->lock_);
 
   if (err != ESP_OK) {
     ESP_LOGW(TAG, "uart_get_buffered_data_len failed: %s", esp_err_to_name(err));
@@ -358,9 +352,7 @@ size_t IDFUARTComponent::available() {
 
 void IDFUARTComponent::flush() {
   ESP_LOGVV(TAG, "    Flushing");
-  xSemaphoreTake(this->lock_, portMAX_DELAY);
   uart_wait_tx_done(this->uart_num_, portMAX_DELAY);
-  xSemaphoreGive(this->lock_);
 }
 
 void IDFUARTComponent::check_logger_conflict() {}
@@ -384,6 +376,13 @@ void IDFUARTComponent::start_rx_event_task_() {
   ESP_LOGV(TAG, "RX event task started");
 }
 
+// FreeRTOS task that relays UART ISR events to the main loop.
+// This task exists because wake_loop_threadsafe() is not ISR-safe (it uses a
+// UDP loopback socket), so we need a task as an ISR-to-main-loop trampoline.
+// IMPORTANT: This task must NOT call any UART wrapper methods (read_array,
+// write_array, peek_byte, etc.) or touch has_peek_/peek_byte_ — all reading
+// is done by the main loop. This task only reads from the event queue and
+// calls App.wake_loop_threadsafe().
 void IDFUARTComponent::rx_event_task_func(void *param) {
   auto *self = static_cast<IDFUARTComponent *>(param);
   uart_event_t event;
@@ -405,8 +404,14 @@ void IDFUARTComponent::rx_event_task_func(void *param) {
 
         case UART_FIFO_OVF:
         case UART_BUFFER_FULL:
-          ESP_LOGW(TAG, "FIFO overflow or ring buffer full - clearing");
-          uart_flush_input(self->uart_num_);
+          // Don't call uart_flush_input() here — this task does not own the read side.
+          // ESP-IDF examples flush on overflow because the same task handles both events
+          // and reads, so flush and read are serialized. Here, reads happen on the main
+          // loop, so flushing from this task races with read_array() and can destroy data
+          // mid-read. The driver self-heals without an explicit flush: uart_read_bytes()
+          // calls uart_check_buf_full() after each chunk, which moves stashed FIFO bytes
+          // into the ring buffer and re-enables RX interrupts once space is freed.
+          ESP_LOGW(TAG, "FIFO overflow or ring buffer full");
 #if defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_WAKE_LOOP_THREADSAFE)
           App.wake_loop_threadsafe();
 #endif

esphome/components/uart/uart_component_esp_idf.h

@@ -8,6 +8,13 @@
 
 namespace esphome::uart {
 
+/// ESP-IDF UART driver wrapper.
+///
+/// Thread safety: All public methods must only be called from the main loop.
+/// The ESP-IDF UART driver API does not guarantee thread safety, and ESPHome's
+/// peek byte state (has_peek_/peek_byte_) is not synchronized. The rx_event_task
+/// (when enabled) must not call any of these methods — it communicates with the
+/// main loop exclusively via App.wake_loop_threadsafe().
 class IDFUARTComponent : public UARTComponent, public Component {
  public:
   void setup() override;
@@ -26,7 +33,9 @@ class IDFUARTComponent : public UARTComponent, public Component {
   void flush() override;
 
   uint8_t get_hw_serial_number() { return this->uart_num_; }
+#ifdef USE_UART_WAKE_LOOP_ON_RX
   QueueHandle_t *get_uart_event_queue() { return &this->uart_event_queue_; }
+#endif
 
   /**
    * Load the UART with the current settings.
@@ -46,18 +55,20 @@ class IDFUARTComponent : public UARTComponent, public Component {
  protected:
   void check_logger_conflict() override;
   uart_port_t uart_num_;
-  QueueHandle_t uart_event_queue_;
   uart_config_t get_config_();
-  SemaphoreHandle_t lock_;
 
   bool has_peek_{false};
   uint8_t peek_byte_;
 
 #ifdef USE_UART_WAKE_LOOP_ON_RX
-  // RX notification support
+  // RX notification support — runs on a separate FreeRTOS task.
+  // IMPORTANT: rx_event_task_func must NOT call any UART wrapper methods (read_array,
+  // write_array, etc.) or touch has_peek_/peek_byte_. It must only read from the
+  // event queue and call App.wake_loop_threadsafe().
   void start_rx_event_task_();
   static void rx_event_task_func(void *param);
 
+  QueueHandle_t uart_event_queue_;
   TaskHandle_t rx_event_task_handle_{nullptr};
 #endif  // USE_UART_WAKE_LOOP_ON_RX
 };

esphome/components/usb_host/usb_host.h

@@ -148,6 +148,7 @@ class USBClient : public Component {
   EventPool<UsbEvent, USB_EVENT_QUEUE_SIZE> event_pool;
 
  protected:
+  void handle_open_state_();
   TransferRequest *get_trq_();  // Lock-free allocation using atomic bitmask (multi-consumer safe)
   virtual void disconnect();
   virtual void on_connected() {}

esphome/components/usb_host/usb_host_client.cpp

@@ -9,6 +9,7 @@
 #include <cinttypes>
 #include <cstring>
 #include <atomic>
+#include <span>
 namespace esphome {
 namespace usb_host {
 
@@ -142,18 +143,23 @@ static void usb_client_print_config_descriptor(const usb_config_desc_t *cfg_desc
   } while (next_desc != NULL);
 }
 #endif
-static std::string get_descriptor_string(const usb_str_desc_t *desc) {
-  char buffer[256];
-  if (desc == nullptr)
+// USB string descriptors: bLength (uint8_t, max 255) includes the 2-byte header (bLength and bDescriptorType).
+// Character count = (bLength - 2) / 2, max 126 chars + null terminator.
+static constexpr size_t DESC_STRING_BUF_SIZE = 128;
+
+static const char *get_descriptor_string(const usb_str_desc_t *desc, std::span<char, DESC_STRING_BUF_SIZE> buffer) {
+  if (desc == nullptr || desc->bLength < 2)
     return "(unspecified)";
-  char *p = buffer;
-  for (int i = 0; i != desc->bLength / 2; i++) {
+  int char_count = (desc->bLength - 2) / 2;
+  char *p = buffer.data();
+  char *end = p + buffer.size() - 1;
+  for (int i = 0; i != char_count && p < end; i++) {
     auto c = desc->wData[i];
     if (c < 0x100)
       *p++ = static_cast<char>(c);
   }
   *p = '\0';
-  return {buffer};
+  return buffer.data();
 }
 
 // CALLBACK CONTEXT: USB task (called from usb_host_client_handle_events in USB task)
@@ -259,60 +265,63 @@ void USBClient::loop() {
     ESP_LOGW(TAG, "Dropped %u USB events due to queue overflow", dropped);
   }
 
-  switch (this->state_) {
-    case USB_CLIENT_OPEN: {
-      int err;
-      ESP_LOGD(TAG, "Open device %d", this->device_addr_);
-      err = usb_host_device_open(this->handle_, this->device_addr_, &this->device_handle_);
-      if (err != ESP_OK) {
-        ESP_LOGW(TAG, "Device open failed: %s", esp_err_to_name(err));
-        this->state_ = USB_CLIENT_INIT;
-        break;
-      }
-      ESP_LOGD(TAG, "Get descriptor device %d", this->device_addr_);
-      const usb_device_desc_t *desc;
-      err = usb_host_get_device_descriptor(this->device_handle_, &desc);
-      if (err != ESP_OK) {
-        ESP_LOGW(TAG, "Device get_desc failed: %s", esp_err_to_name(err));
-        this->disconnect();
-      } else {
-        ESP_LOGD(TAG, "Device descriptor: vid %X pid %X", desc->idVendor, desc->idProduct);
-        if (desc->idVendor == this->vid_ && desc->idProduct == this->pid_ || this->vid_ == 0 && this->pid_ == 0) {
-          usb_device_info_t dev_info;
-          err = usb_host_device_info(this->device_handle_, &dev_info);
-          if (err != ESP_OK) {
-            ESP_LOGW(TAG, "Device info failed: %s", esp_err_to_name(err));
-            this->disconnect();
-            break;
-          }
-          this->state_ = USB_CLIENT_CONNECTED;
-          ESP_LOGD(TAG, "Device connected: Manuf: %s; Prod: %s; Serial: %s",
-                   get_descriptor_string(dev_info.str_desc_manufacturer).c_str(),
-                   get_descriptor_string(dev_info.str_desc_product).c_str(),
-                   get_descriptor_string(dev_info.str_desc_serial_num).c_str());
+  if (this->state_ == USB_CLIENT_OPEN) {
+    this->handle_open_state_();
+  }
+}
+
+void USBClient::handle_open_state_() {
+  int err;
+  ESP_LOGD(TAG, "Open device %d", this->device_addr_);
+  err = usb_host_device_open(this->handle_, this->device_addr_, &this->device_handle_);
+  if (err != ESP_OK) {
+    ESP_LOGW(TAG, "Device open failed: %s", esp_err_to_name(err));
+    this->state_ = USB_CLIENT_INIT;
+    return;
+  }
+  ESP_LOGD(TAG, "Get descriptor device %d", this->device_addr_);
+  const usb_device_desc_t *desc;
+  err = usb_host_get_device_descriptor(this->device_handle_, &desc);
+  if (err != ESP_OK) {
+    ESP_LOGW(TAG, "Device get_desc failed: %s", esp_err_to_name(err));
+    this->disconnect();
+    return;
+  }
+  ESP_LOGD(TAG, "Device descriptor: vid %X pid %X", desc->idVendor, desc->idProduct);
+  if (desc->idVendor != this->vid_ || desc->idProduct != this->pid_) {
+    if (this->vid_ != 0 || this->pid_ != 0) {
+      ESP_LOGD(TAG, "Not our device, closing");
+      this->disconnect();
+      return;
+    }
+  }
+  usb_device_info_t dev_info;
+  err = usb_host_device_info(this->device_handle_, &dev_info);
+  if (err != ESP_OK) {
+    ESP_LOGW(TAG, "Device info failed: %s", esp_err_to_name(err));
+    this->disconnect();
+    return;
+  }
+  this->state_ = USB_CLIENT_CONNECTED;
+  char buf_manuf[DESC_STRING_BUF_SIZE];
+  char buf_product[DESC_STRING_BUF_SIZE];
+  char buf_serial[DESC_STRING_BUF_SIZE];
+  ESP_LOGD(TAG, "Device connected: Manuf: %s; Prod: %s; Serial: %s",
+           get_descriptor_string(dev_info.str_desc_manufacturer, buf_manuf),
+           get_descriptor_string(dev_info.str_desc_product, buf_product),
+           get_descriptor_string(dev_info.str_desc_serial_num, buf_serial));
 
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
-          const usb_device_desc_t *device_desc;
-          err = usb_host_get_device_descriptor(this->device_handle_, &device_desc);
-          if (err == ESP_OK)
-            usb_client_print_device_descriptor(device_desc);
-          const usb_config_desc_t *config_desc;
-          err = usb_host_get_active_config_descriptor(this->device_handle_, &config_desc);
-          if (err == ESP_OK)
-            usb_client_print_config_descriptor(config_desc, nullptr);
+  const usb_device_desc_t *device_desc;
+  err = usb_host_get_device_descriptor(this->device_handle_, &device_desc);
+  if (err == ESP_OK)
+    usb_client_print_device_descriptor(device_desc);
+  const usb_config_desc_t *config_desc;
+  err = usb_host_get_active_config_descriptor(this->device_handle_, &config_desc);
+  if (err == ESP_OK)
+    usb_client_print_config_descriptor(config_desc, nullptr);
 #endif
-          this->on_connected();
-        } else {
-          ESP_LOGD(TAG, "Not our device, closing");
-          this->disconnect();
-        }
-      }
-      break;
-    }
-
-    default:
-      break;
-  }
+  this->on_connected();
 }
 
 void USBClient::on_opened(uint8_t addr) {

esphome/components/web_server/web_server.cpp

@@ -198,7 +198,8 @@ EntityMatchResult UrlMatch::match_entity(EntityBase *entity) const {
 
 #if !defined(USE_ESP32) && defined(USE_ARDUINO)
 // helper for allowing only unique entries in the queue
-void DeferredUpdateEventSource::deq_push_back_with_dedup_(void *source, message_generator_t *message_generator) {
+void __attribute__((flatten))
+DeferredUpdateEventSource::deq_push_back_with_dedup_(void *source, message_generator_t *message_generator) {
   DeferredEvent item(source, message_generator);
 
   // Use range-based for loop instead of std::find_if to reduce template instantiation overhead and binary size
@@ -557,7 +558,9 @@ static void set_json_id(JsonObject &root, EntityBase *obj, const char *prefix, J
       root[ESPHOME_F("device")] = device_name;
     }
 #endif
+#ifdef USE_ENTITY_ICON
     root[ESPHOME_F("icon")] = obj->get_icon_ref();
+#endif
     root[ESPHOME_F("entity_category")] = obj->get_entity_category();
     bool is_disabled = obj->is_disabled_by_default();
     if (is_disabled)
@@ -583,8 +586,7 @@ static void set_json_icon_state_value(JsonObject &root, EntityBase *obj, const c
 
 // Helper to get request detail parameter
 static JsonDetail get_request_detail(AsyncWebServerRequest *request) {
-  auto *param = request->getParam(ESPHOME_F("detail"));
-  return (param && param->value() == "all") ? DETAIL_ALL : DETAIL_STATE;
+  return request->arg(ESPHOME_F("detail")) == "all" ? DETAIL_ALL : DETAIL_STATE;
 }
 
 #ifdef USE_SENSOR
@@ -861,10 +863,10 @@ void WebServer::handle_fan_request(AsyncWebServerRequest *request, const UrlMatc
       }
       auto call = is_on ? obj->turn_on() : obj->turn_off();
 
-      parse_int_param_(request, ESPHOME_F("speed_level"), call, &decltype(call)::set_speed);
+      parse_num_param_(request, ESPHOME_F("speed_level"), call, &decltype(call)::set_speed);
 
-      if (request->hasParam(ESPHOME_F("oscillation"))) {
-        auto speed = request->getParam(ESPHOME_F("oscillation"))->value();
+      if (request->hasArg(ESPHOME_F("oscillation"))) {
+        auto speed = request->arg(ESPHOME_F("oscillation"));
         auto val = parse_on_off(speed.c_str());
         switch (val) {
           case PARSE_ON:
@@ -1040,14 +1042,14 @@ void WebServer::handle_cover_request(AsyncWebServerRequest *request, const UrlMa
     }
 
     auto traits = obj->get_traits();
-    if ((request->hasParam(ESPHOME_F("position")) && !traits.get_supports_position()) ||
-        (request->hasParam(ESPHOME_F("tilt")) && !traits.get_supports_tilt())) {
+    if ((request->hasArg(ESPHOME_F("position")) && !traits.get_supports_position()) ||
+        (request->hasArg(ESPHOME_F("tilt")) && !traits.get_supports_tilt())) {
       request->send(409);
       return;
     }
 
-    parse_float_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
-    parse_float_param_(request, ESPHOME_F("tilt"), call, &decltype(call)::set_tilt);
+    parse_num_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
+    parse_num_param_(request, ESPHOME_F("tilt"), call, &decltype(call)::set_tilt);
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1106,7 +1108,7 @@ void WebServer::handle_number_request(AsyncWebServerRequest *request, const UrlM
     }
 
     auto call = obj->make_call();
-    parse_float_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_value);
+    parse_num_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_value);
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1174,12 +1176,13 @@ void WebServer::handle_date_request(AsyncWebServerRequest *request, const UrlMat
 
     auto call = obj->make_call();
 
-    if (!request->hasParam(ESPHOME_F("value"))) {
+    const auto &value = request->arg(ESPHOME_F("value"));
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (value.length() == 0) {  // NOLINT(readability-container-size-empty)
       request->send(409);
       return;
     }
-
-    parse_string_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_date);
+    call.set_date(value.c_str(), value.length());
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1234,12 +1237,13 @@ void WebServer::handle_time_request(AsyncWebServerRequest *request, const UrlMat
 
     auto call = obj->make_call();
 
-    if (!request->hasParam(ESPHOME_F("value"))) {
+    const auto &value = request->arg(ESPHOME_F("value"));
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (value.length() == 0) {  // NOLINT(readability-container-size-empty)
       request->send(409);
       return;
     }
-
-    parse_string_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_time);
+    call.set_time(value.c_str(), value.length());
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1293,12 +1297,13 @@ void WebServer::handle_datetime_request(AsyncWebServerRequest *request, const Ur
 
     auto call = obj->make_call();
 
-    if (!request->hasParam(ESPHOME_F("value"))) {
+    const auto &value = request->arg(ESPHOME_F("value"));
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (value.length() == 0) {  // NOLINT(readability-container-size-empty)
       request->send(409);
       return;
     }
-
-    parse_string_param_(request, ESPHOME_F("value"), call, &decltype(call)::set_datetime);
+    call.set_datetime(value.c_str(), value.length());
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1477,10 +1482,14 @@ void WebServer::handle_climate_request(AsyncWebServerRequest *request, const Url
     parse_string_param_(request, ESPHOME_F("swing_mode"), call, &decltype(call)::set_swing_mode);
 
     // Parse temperature parameters
-    parse_float_param_(request, ESPHOME_F("target_temperature_high"), call,
-                       &decltype(call)::set_target_temperature_high);
-    parse_float_param_(request, ESPHOME_F("target_temperature_low"), call, &decltype(call)::set_target_temperature_low);
-    parse_float_param_(request, ESPHOME_F("target_temperature"), call, &decltype(call)::set_target_temperature);
+    // static_cast needed to disambiguate overloaded setters (float vs optional<float>)
+    using ClimateCall = decltype(call);
+    parse_num_param_(request, ESPHOME_F("target_temperature_high"), call,
+                     static_cast<ClimateCall &(ClimateCall::*) (float)>(&ClimateCall::set_target_temperature_high));
+    parse_num_param_(request, ESPHOME_F("target_temperature_low"), call,
+                     static_cast<ClimateCall &(ClimateCall::*) (float)>(&ClimateCall::set_target_temperature_low));
+    parse_num_param_(request, ESPHOME_F("target_temperature"), call,
+                     static_cast<ClimateCall &(ClimateCall::*) (float)>(&ClimateCall::set_target_temperature));
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1721,12 +1730,12 @@ void WebServer::handle_valve_request(AsyncWebServerRequest *request, const UrlMa
     }
 
     auto traits = obj->get_traits();
-    if (request->hasParam(ESPHOME_F("position")) && !traits.get_supports_position()) {
+    if (request->hasArg(ESPHOME_F("position")) && !traits.get_supports_position()) {
       request->send(409);
       return;
     }
 
-    parse_float_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
+    parse_num_param_(request, ESPHOME_F("position"), call, &decltype(call)::set_position);
 
     DEFER_ACTION(call, call.perform());
     request->send(200);
@@ -1870,12 +1879,12 @@ void WebServer::handle_water_heater_request(AsyncWebServerRequest *request, cons
     parse_string_param_(request, ESPHOME_F("mode"), base_call, &water_heater::WaterHeaterCall::set_mode);
 
     // Parse temperature parameters
-    parse_float_param_(request, ESPHOME_F("target_temperature"), base_call,
-                       &water_heater::WaterHeaterCall::set_target_temperature);
-    parse_float_param_(request, ESPHOME_F("target_temperature_low"), base_call,
-                       &water_heater::WaterHeaterCall::set_target_temperature_low);
-    parse_float_param_(request, ESPHOME_F("target_temperature_high"), base_call,
-                       &water_heater::WaterHeaterCall::set_target_temperature_high);
+    parse_num_param_(request, ESPHOME_F("target_temperature"), base_call,
+                     &water_heater::WaterHeaterCall::set_target_temperature);
+    parse_num_param_(request, ESPHOME_F("target_temperature_low"), base_call,
+                     &water_heater::WaterHeaterCall::set_target_temperature_low);
+    parse_num_param_(request, ESPHOME_F("target_temperature_high"), base_call,
+                     &water_heater::WaterHeaterCall::set_target_temperature_high);
 
     // Parse away mode parameter
     parse_bool_param_(request, ESPHOME_F("away"), base_call, &water_heater::WaterHeaterCall::set_away);
@@ -1979,16 +1988,16 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
     auto call = obj->make_call();
 
     // Parse carrier frequency (optional)
-    if (request->hasParam(ESPHOME_F("carrier_frequency"))) {
-      auto value = parse_number<uint32_t>(request->getParam(ESPHOME_F("carrier_frequency"))->value().c_str());
+    {
+      auto value = parse_number<uint32_t>(request->arg(ESPHOME_F("carrier_frequency")).c_str());
       if (value.has_value()) {
         call.set_carrier_frequency(*value);
       }
     }
 
     // Parse repeat count (optional, defaults to 1)
-    if (request->hasParam(ESPHOME_F("repeat_count"))) {
-      auto value = parse_number<uint32_t>(request->getParam(ESPHOME_F("repeat_count"))->value().c_str());
+    {
+      auto value = parse_number<uint32_t>(request->arg(ESPHOME_F("repeat_count")).c_str());
       if (value.has_value()) {
         call.set_repeat_count(*value);
       }
@@ -1996,18 +2005,12 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
 
     // Parse base64url-encoded raw timings (required)
     // Base64url is URL-safe: uses A-Za-z0-9-_ (no special characters needing escaping)
-    if (!request->hasParam(ESPHOME_F("data"))) {
-      request->send(400, ESPHOME_F("text/plain"), ESPHOME_F("Missing 'data' parameter"));
-      return;
-    }
+    const auto &data_arg = request->arg(ESPHOME_F("data"));
 
-    // .c_str() is required for Arduino framework where value() returns Arduino String instead of std::string
-    std::string encoded =
-        request->getParam(ESPHOME_F("data"))->value().c_str();  // NOLINT(readability-redundant-string-cstr)
-
-    // Validate base64url is not empty
-    if (encoded.empty()) {
-      request->send(400, ESPHOME_F("text/plain"), ESPHOME_F("Empty 'data' parameter"));
+    // Validate base64url is not empty (also catches missing parameter since arg() returns empty string)
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (data_arg.length() == 0) {  // NOLINT(readability-container-size-empty)
+      request->send(400, ESPHOME_F("text/plain"), ESPHOME_F("Missing or empty 'data' parameter"));
       return;
     }
 
@@ -2015,7 +2018,7 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
     // it outlives the call - set_raw_timings_base64url stores a pointer, so the string
     // must remain valid until perform() completes.
     // ESP8266 also needs this because ESPAsyncWebServer callbacks run in "sys" context.
-    this->defer([call, encoded = std::move(encoded)]() mutable {
+    this->defer([call, encoded = std::string(data_arg.c_str(), data_arg.length())]() mutable {
       call.set_raw_timings_base64url(encoded);
       call.perform();
     });

esphome/components/web_server/web_server.h

@@ -513,11 +513,9 @@ class WebServer : public Controller,
   template<typename T, typename Ret>
   void parse_light_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(float),
                           float scale = 1.0f) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<float>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value / scale);
-      }
+    auto value = parse_number<float>(request->arg(param_name).c_str());
+    if (value.has_value()) {
+      (call.*setter)(*value / scale);
     }
   }
 
@@ -525,34 +523,19 @@ class WebServer : public Controller,
   template<typename T, typename Ret>
   void parse_light_param_uint_(AsyncWebServerRequest *request, ParamNameType param_name, T &call,
                                Ret (T::*setter)(uint32_t), uint32_t scale = 1) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<uint32_t>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value * scale);
-      }
+    auto value = parse_number<uint32_t>(request->arg(param_name).c_str());
+    if (value.has_value()) {
+      (call.*setter)(*value * scale);
     }
   }
 #endif
 
-  // Generic helper to parse and apply a float parameter
-  template<typename T, typename Ret>
-  void parse_float_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(float)) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<float>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value);
-      }
-    }
-  }
-
-  // Generic helper to parse and apply an int parameter
-  template<typename T, typename Ret>
-  void parse_int_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(int)) {
-    if (request->hasParam(param_name)) {
-      auto value = parse_number<int>(request->getParam(param_name)->value().c_str());
-      if (value.has_value()) {
-        (call.*setter)(*value);
-      }
+  // Generic helper to parse and apply a numeric parameter
+  template<typename NumT, typename T, typename Ret>
+  void parse_num_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(NumT)) {
+    auto value = parse_number<NumT>(request->arg(param_name).c_str());
+    if (value.has_value()) {
+      (call.*setter)(*value);
     }
   }
 
@@ -560,10 +543,9 @@ class WebServer : public Controller,
   template<typename T, typename Ret>
   void parse_string_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call,
                            Ret (T::*setter)(const std::string &)) {
-    if (request->hasParam(param_name)) {
-      // .c_str() is required for Arduino framework where value() returns Arduino String instead of std::string
-      std::string value = request->getParam(param_name)->value().c_str();  // NOLINT(readability-redundant-string-cstr)
-      (call.*setter)(value);
+    if (request->hasArg(param_name)) {
+      const auto &value = request->arg(param_name);
+      (call.*setter)(std::string(value.c_str(), value.length()));
     }
   }
 
@@ -573,8 +555,9 @@ class WebServer : public Controller,
   // Invalid values are ignored (setter not called)
   template<typename T, typename Ret>
   void parse_bool_param_(AsyncWebServerRequest *request, ParamNameType param_name, T &call, Ret (T::*setter)(bool)) {
-    if (request->hasParam(param_name)) {
-      auto param_value = request->getParam(param_name)->value();
+    const auto &param_value = request->arg(param_name);
+    // Arduino String has isEmpty() not empty(), use length() for cross-platform compatibility
+    if (param_value.length() > 0) {  // NOLINT(readability-container-size-empty)
       // First check on/off (default), then true/false (custom)
       auto val = parse_on_off(param_value.c_str());
       if (val == PARSE_NONE) {

esphome/components/web_server_idf/utils.cpp

@@ -1,17 +1,13 @@
 #ifdef USE_ESP32
-#include <memory>
 #include <cstring>
 #include <cctype>
 #include "esphome/core/helpers.h"
-#include "esphome/core/log.h"
 #include "http_parser.h"
 
 #include "utils.h"
 
 namespace esphome::web_server_idf {
 
-static const char *const TAG = "web_server_idf_utils";
-
 size_t url_decode(char *str) {
   char *start = str;
   char *ptr = str, buf;
@@ -54,32 +50,15 @@ optional<std::string> request_get_header(httpd_req_t *req, const char *name) {
   return {str};
 }
 
-optional<std::string> request_get_url_query(httpd_req_t *req) {
-  auto len = httpd_req_get_url_query_len(req);
-  if (len == 0) {
-    return {};
-  }
-
-  std::string str;
-  str.resize(len);
-
-  auto res = httpd_req_get_url_query_str(req, &str[0], len + 1);
-  if (res != ESP_OK) {
-    ESP_LOGW(TAG, "Can't get query for request: %s", esp_err_to_name(res));
-    return {};
-  }
-
-  return {str};
-}
-
 optional<std::string> query_key_value(const char *query_url, size_t query_len, const char *key) {
   if (query_url == nullptr || query_len == 0) {
     return {};
   }
 
-  // Use stack buffer for typical query strings, heap fallback for large ones
-  SmallBufferWithHeapFallback<256, char> val(query_len);
-
+  // Value can't exceed query_len. Use small stack buffer for typical values,
+  // heap fallback for long ones (e.g. base64 IR data) to limit stack usage
+  // since callers may also have stack buffers for the query string.
+  SmallBufferWithHeapFallback<128, char> val(query_len);
   if (httpd_query_key_value(query_url, key, val.get(), query_len) != ESP_OK) {
     return {};
   }
@@ -88,6 +67,18 @@ optional<std::string> query_key_value(const char *query_url, size_t query_len, c
   return {val.get()};
 }
 
+bool query_has_key(const char *query_url, size_t query_len, const char *key) {
+  if (query_url == nullptr || query_len == 0) {
+    return false;
+  }
+  // Minimal buffer — we only care if the key exists, not the value
+  char buf[1];
+  // httpd_query_key_value returns ESP_OK if found, ESP_ERR_HTTPD_RESULT_TRUNC if found
+  // but value truncated (expected with 1-byte buffer), or other errors for invalid input
+  auto err = httpd_query_key_value(query_url, key, buf, sizeof(buf));
+  return err == ESP_OK || err == ESP_ERR_HTTPD_RESULT_TRUNC;
+}
+
 // Helper function for case-insensitive string region comparison
 bool str_ncmp_ci(const char *s1, const char *s2, size_t n) {
   for (size_t i = 0; i < n; i++) {

esphome/components/web_server_idf/utils.h

@@ -13,11 +13,8 @@ size_t url_decode(char *str);
 
 bool request_has_header(httpd_req_t *req, const char *name);
 optional<std::string> request_get_header(httpd_req_t *req, const char *name);
-optional<std::string> request_get_url_query(httpd_req_t *req);
 optional<std::string> query_key_value(const char *query_url, size_t query_len, const char *key);
-inline optional<std::string> query_key_value(const std::string &query_url, const std::string &key) {
-  return query_key_value(query_url.c_str(), query_url.size(), key.c_str());
-}
+bool query_has_key(const char *query_url, size_t query_len, const char *key);
 
 // Helper function for case-insensitive character comparison
 inline bool char_equals_ci(char a, char b) { return ::tolower(a) == ::tolower(b); }

esphome/components/web_server_idf/web_server_idf.cpp

@@ -393,13 +393,7 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   }
 
   // Look up value from query strings
-  optional<std::string> val = query_key_value(this->post_query_.c_str(), this->post_query_.size(), name);
-  if (!val.has_value()) {
-    auto url_query = request_get_url_query(*this);
-    if (url_query.has_value()) {
-      val = query_key_value(url_query.value().c_str(), url_query.value().size(), name);
-    }
-  }
+  auto val = this->find_query_value_(name);
 
   // Don't cache misses to avoid wasting memory when handlers check for
   // optional parameters that don't exist in the request
@@ -412,6 +406,50 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   return param;
 }
 
+/// Search post_query then URL query with a callback.
+/// Returns first truthy result, or value-initialized default.
+/// URL query is accessed directly from req->uri (same pattern as url_to()).
+template<typename Func>
+static auto search_query_sources(httpd_req_t *req, const std::string &post_query, const char *name, Func func)
+    -> decltype(func(nullptr, size_t{0}, name)) {
+  if (!post_query.empty()) {
+    auto result = func(post_query.c_str(), post_query.size(), name);
+    if (result) {
+      return result;
+    }
+  }
+  // Use httpd API for query length, then access string directly from URI.
+  // http_parser identifies components by offset/length without modifying the URI string.
+  // This is the same pattern used by url_to().
+  auto len = httpd_req_get_url_query_len(req);
+  if (len == 0) {
+    return {};
+  }
+  const char *query = strchr(req->uri, '?');
+  if (query == nullptr) {
+    return {};
+  }
+  query++;  // skip '?'
+  return func(query, len, name);
+}
+
+optional<std::string> AsyncWebServerRequest::find_query_value_(const char *name) const {
+  return search_query_sources(this->req_, this->post_query_, name,
+                              [](const char *q, size_t len, const char *k) { return query_key_value(q, len, k); });
+}
+
+bool AsyncWebServerRequest::hasArg(const char *name) {
+  return search_query_sources(this->req_, this->post_query_, name, query_has_key);
+}
+
+std::string AsyncWebServerRequest::arg(const char *name) {
+  auto val = this->find_query_value_(name);
+  if (val.has_value()) {
+    return std::move(val.value());
+  }
+  return {};
+}
+
 void AsyncWebServerResponse::addHeader(const char *name, const char *value) {
   httpd_resp_set_hdr(*this->req_, name, value);
 }

esphome/components/web_server_idf/web_server_idf.h

@@ -116,7 +116,8 @@ class AsyncWebServerRequest {
   /// Write URL (without query string) to buffer, returns StringRef pointing to buffer.
   /// URL is decoded (e.g., %20 -> space).
   StringRef url_to(std::span<char, URL_BUF_SIZE> buffer) const;
-  /// Get URL as std::string. Prefer url_to() to avoid heap allocation.
+  // Remove before 2026.9.0
+  ESPDEPRECATED("Use url_to() instead. Removed in 2026.9.0", "2026.3.0")
   std::string url() const {
     char buffer[URL_BUF_SIZE];
     return std::string(this->url_to(buffer));
@@ -170,14 +171,8 @@ class AsyncWebServerRequest {
   AsyncWebParameter *getParam(const std::string &name) { return this->getParam(name.c_str()); }
 
   // NOLINTNEXTLINE(readability-identifier-naming)
-  bool hasArg(const char *name) { return this->hasParam(name); }
-  std::string arg(const char *name) {
-    auto *param = this->getParam(name);
-    if (param) {
-      return param->value();
-    }
-    return {};
-  }
+  bool hasArg(const char *name);
+  std::string arg(const char *name);
   std::string arg(const std::string &name) { return this->arg(name.c_str()); }
 
   operator httpd_req_t *() const { return this->req_; }
@@ -192,6 +187,7 @@ class AsyncWebServerRequest {
   // is faster than tree/hash overhead. AsyncWebParameter stores both name and value to avoid
   // duplicate storage. Only successful lookups are cached to prevent cache pollution when
   // handlers check for optional parameters that don't exist.
+  optional<std::string> find_query_value_(const char *name) const;
   std::vector<AsyncWebParameter *> params_;
   std::string post_query_;
   AsyncWebServerRequest(httpd_req_t *req) : req_(req) {}

esphome/components/wifi/wifi_component.cpp

@@ -487,6 +487,19 @@ bool WiFiComponent::matches_configured_network_(const char *ssid, const uint8_t
   return false;
 }
 
+void __attribute__((flatten)) WiFiComponent::set_sta_priority(bssid_t bssid, int8_t priority) {
+  for (auto &it : this->sta_priorities_) {
+    if (it.bssid == bssid) {
+      it.priority = priority;
+      return;
+    }
+  }
+  this->sta_priorities_.push_back(WiFiSTAPriority{
+      .bssid = bssid,
+      .priority = priority,
+  });
+}
+
 void WiFiComponent::log_discarded_scan_result_(const char *ssid, const uint8_t *bssid, int8_t rssi, uint8_t channel) {
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
   // Skip logging during roaming scans to avoid log buffer overflow

esphome/components/wifi/wifi_component.h

@@ -488,20 +488,11 @@ class WiFiComponent : public Component {
     }
     return 0;
   }
-  void set_sta_priority(const bssid_t bssid, int8_t priority) {
-    for (auto &it : this->sta_priorities_) {
-      if (it.bssid == bssid) {
-        it.priority = priority;
-        return;
-      }
-    }
-    this->sta_priorities_.push_back(WiFiSTAPriority{
-        .bssid = bssid,
-        .priority = priority,
-    });
-  }
+  void set_sta_priority(bssid_t bssid, int8_t priority);
 
   network::IPAddresses wifi_sta_ip_addresses();
+  // Remove before 2026.9.0
+  ESPDEPRECATED("Use wifi_ssid_to() instead. Removed in 2026.9.0", "2026.3.0")
   std::string wifi_ssid();
   /// Write SSID to buffer without heap allocation.
   /// Returns pointer to buffer, or empty string if not connected.

esphome/core/application.h

@@ -94,6 +94,9 @@
 #ifdef USE_INFRARED
 #include "esphome/components/infrared/infrared.h"
 #endif
+#ifdef USE_SERIAL_PROXY
+#include "esphome/components/serial_proxy/serial_proxy.h"
+#endif
 #ifdef USE_EVENT
 #include "esphome/components/event/event.h"
 #endif
@@ -234,6 +237,13 @@ class Application {
   void register_infrared(infrared::Infrared *infrared) { this->infrareds_.push_back(infrared); }
 #endif
 
+#ifdef USE_SERIAL_PROXY
+  void register_serial_proxy(serial_proxy::SerialProxy *proxy) {
+    proxy->set_instance_index(this->serial_proxies_.size());
+    this->serial_proxies_.push_back(proxy);
+  }
+#endif
+
 #ifdef USE_EVENT
   void register_event(event::Event *event) { this->events_.push_back(event); }
 #endif
@@ -473,6 +483,10 @@ class Application {
   GET_ENTITY_METHOD(infrared::Infrared, infrared, infrareds)
 #endif
 
+#ifdef USE_SERIAL_PROXY
+  auto &get_serial_proxies() const { return this->serial_proxies_; }
+#endif
+
 #ifdef USE_EVENT
   auto &get_events() const { return this->events_; }
   GET_ENTITY_METHOD(event::Event, event, events)
@@ -690,6 +704,9 @@ class Application {
 #ifdef USE_INFRARED
   StaticVector<infrared::Infrared *, ESPHOME_ENTITY_INFRARED_COUNT> infrareds_{};
 #endif
+#ifdef USE_SERIAL_PROXY
+  std::vector<serial_proxy::SerialProxy *> serial_proxies_{};
+#endif
 #ifdef USE_UPDATE
   StaticVector<update::UpdateEntity *, ESPHOME_ENTITY_UPDATE_COUNT> updates_{};
 #endif

esphome/core/defines.h

@@ -99,6 +99,7 @@
 #define MDNS_SERVICE_COUNT 3
 #define USE_MDNS_DYNAMIC_TXT
 #define MDNS_DYNAMIC_TXT_COUNT 2
+#define SERIAL_PROXY_COUNT 2
 #define SNTP_SERVER_COUNT 3
 #define USE_MEDIA_PLAYER
 #define USE_NEXTION_TFT_UPLOAD
@@ -109,6 +110,7 @@
 #define USE_SAFE_MODE_CALLBACK
 #define USE_SELECT
 #define USE_SENSOR
+#define USE_SERIAL_PROXY
 #define USE_STATUS_LED
 #define USE_STATUS_SENSOR
 #define USE_SWITCH
@@ -148,9 +150,9 @@
 #define USE_MQTT
 #define USE_MQTT_COVER_JSON
 #define USE_NETWORK
-#define USE_ONLINE_IMAGE_BMP_SUPPORT
-#define USE_ONLINE_IMAGE_PNG_SUPPORT
-#define USE_ONLINE_IMAGE_JPEG_SUPPORT
+#define USE_RUNTIME_IMAGE_BMP
+#define USE_RUNTIME_IMAGE_PNG
+#define USE_RUNTIME_IMAGE_JPEG
 #define USE_OTA
 #define USE_OTA_PASSWORD
 #define USE_OTA_STATE_LISTENER

esphome/core/helpers.h

@@ -1083,6 +1083,9 @@ template<std::size_t N> std::string format_hex(const std::array<uint8_t, N> &dat
  * Each byte is displayed as a two-digit uppercase hex value, separated by the specified separator.
  * Optionally includes the total byte count in parentheses at the end.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Pointer to the byte array to format.
  * @param length Number of bytes in the array.
  * @param separator Character to use between hex bytes (default: '.').
@@ -1108,6 +1111,9 @@ std::string format_hex_pretty(const uint8_t *data, size_t length, char separator
  *
  * Similar to the byte array version, but formats 16-bit words as 4-digit hex values.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Pointer to the 16-bit word array to format.
  * @param length Number of 16-bit words in the array.
  * @param separator Character to use between hex words (default: '.').
@@ -1131,6 +1137,9 @@ std::string format_hex_pretty(const uint16_t *data, size_t length, char separato
  * Convenience overload for std::vector<uint8_t>. Formats each byte as a two-digit
  * uppercase hex value with customizable separator.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Vector of bytes to format.
  * @param separator Character to use between hex bytes (default: '.').
  * @param show_length Whether to append the byte count in parentheses (default: true).
@@ -1154,6 +1163,9 @@ std::string format_hex_pretty(const std::vector<uint8_t> &data, char separator =
  * Convenience overload for std::vector<uint16_t>. Each 16-bit word is formatted
  * as a 4-digit uppercase hex value in big-endian order.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data Vector of 16-bit words to format.
  * @param separator Character to use between hex words (default: '.').
  * @param show_length Whether to append the word count in parentheses (default: true).
@@ -1176,6 +1188,9 @@ std::string format_hex_pretty(const std::vector<uint16_t> &data, char separator
  * Treats each character in the string as a byte and formats it in hex.
  * Useful for debugging binary data stored in std::string containers.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @param data String whose bytes should be formatted as hex.
  * @param separator Character to use between hex bytes (default: '.').
  * @param show_length Whether to append the byte count in parentheses (default: true).
@@ -1198,6 +1213,9 @@ std::string format_hex_pretty(const std::string &data, char separator = '.', boo
  * Converts the integer to big-endian byte order and formats each byte as hex.
  * The most significant byte appears first in the output string.
  *
+ * @warning Allocates heap memory. Use format_hex_pretty_to() with a stack buffer instead.
+ * Causes heap fragmentation on long-running devices.
+ *
  * @tparam T Unsigned integer type (uint8_t, uint16_t, uint32_t, uint64_t, etc.).
  * @param val The unsigned integer value to format.
  * @param separator Character to use between hex bytes (default: '.').

platformio.ini

@@ -136,7 +136,7 @@ extends = common:arduino
 platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.37/platform-espressif32.zip
 platform_packages =
     pioarduino/framework-arduinoespressif32@https://github.com/espressif/arduino-esp32/releases/download/3.3.7/esp32-core-3.3.7.tar.xz
-    pioarduino/framework-espidf@https://github.com/pioarduino/esp-idf/releases/download/v5.5.2.260206/esp-idf-v5.5.2.tar.xz
+    pioarduino/framework-espidf@https://github.com/pioarduino/esp-idf/releases/download/v5.5.2/esp-idf-v5.5.2.tar.xz
 
 framework = arduino, espidf  ; Arduino as an ESP-IDF component
 lib_deps =
@@ -171,7 +171,7 @@ extra_scripts = post:esphome/components/esp32/post_build.py.script
 extends = common:idf
 platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.37/platform-espressif32.zip
 platform_packages =
-    pioarduino/framework-espidf@https://github.com/pioarduino/esp-idf/releases/download/v5.5.2.260206/esp-idf-v5.5.2.tar.xz
+    pioarduino/framework-espidf@https://github.com/pioarduino/esp-idf/releases/download/v5.5.2/esp-idf-v5.5.2.tar.xz
 
 framework = espidf
 lib_deps =

script/build_language_schema.py

@@ -369,7 +369,7 @@ def get_logger_tags():
         "api.service",
     ]
     for file in CORE_COMPONENTS_PATH.rglob("*.cpp"):
-        data = file.read_text()
+        data = file.read_text(encoding="utf-8")
         match = pattern.search(data)
         if match:
             tags.append(match.group(1))

tests/components/serial_proxy/common.yaml

@@ -0,0 +1,10 @@
+wifi:
+  ssid: MySSID
+  password: password1
+
+api:
+
+serial_proxy:
+  - id: serial_proxy_1
+    name: Test Serial Port
+    port_type: RS232

tests/components/serial_proxy/test.esp32-idf.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO4
+  rx_pin: GPIO5
+
+packages:
+  uart: !include ../../test_build_components/common/uart/esp32-idf.yaml
+
+<<: !include common.yaml

tests/components/serial_proxy/test.esp8266-ard.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO0
+  rx_pin: GPIO2
+
+packages:
+  uart: !include ../../test_build_components/common/uart/esp8266-ard.yaml
+
+<<: !include common.yaml

tests/components/serial_proxy/test.rp2040-ard.yaml

@@ -0,0 +1,8 @@
+substitutions:
+  tx_pin: GPIO4
+  rx_pin: GPIO5
+
+packages:
+  uart: !include ../../test_build_components/common/uart/rp2040-ard.yaml
+
+<<: !include common.yaml

tests/integration/test_alarm_control_panel_state_transitions.py

@@ -270,6 +270,14 @@ async def test_alarm_control_panel_state_transitions(
         # The chime_sensor has chime: true, so opening it while disarmed
         # should trigger on_chime callback
 
+        # Set up future for the on_ready from opening the chime sensor
+        # (alarm becomes "not ready" when chime sensor opens).
+        # We must wait for this BEFORE creating the close future, otherwise
+        # the open event's log can arrive late and resolve the close future,
+        # causing the test to proceed before the chime close is processed.
+        ready_after_chime_open: asyncio.Future[bool] = loop.create_future()
+        ready_futures.append(ready_after_chime_open)
+
         # We're currently DISARMED - open the chime sensor
         client.switch_command(chime_switch_info.key, True)
 
@@ -279,11 +287,18 @@ async def test_alarm_control_panel_state_transitions(
         except TimeoutError:
             pytest.fail(f"on_chime callback not fired. Log lines: {log_lines[-20:]}")
 
-        # Close the chime sensor and wait for alarm to become ready again
-        # We need to wait for this transition before testing door sensor,
-        # otherwise there's a race where the door sensor state change could
-        # arrive before the chime sensor state change, leaving the alarm in
-        # a continuous "not ready" state with no on_ready callback fired.
+        # Wait for the on_ready from the chime sensor opening
+        try:
+            await asyncio.wait_for(ready_after_chime_open, timeout=2.0)
+        except TimeoutError:
+            pytest.fail(
+                f"on_ready callback not fired when chime sensor opened. "
+                f"Log lines: {log_lines[-20:]}"
+            )
+
+        # Now create the future for the close event and close the sensor.
+        # Since we waited for the open event above, the close event's
+        # on_ready log cannot be confused with the open event's.
         ready_after_chime_close: asyncio.Future[bool] = loop.create_future()
         ready_futures.append(ready_after_chime_close)